Tags vs Custom Fields:Which Fact Goes Where in Your CRM

Tags vs custom fields comes down to one question: how many values can one contact hold? Use a custom field for a fact every contact has exactly one value of, like country, stage or source. Use a tag for a fact some contacts have and others don't. Zero or many goes in a tag.

Tags vs custom fields: the one-line rule

Your CRM gives you two ways to write something down. A structured field. A free-form tag. Most messy contact bases come from mixing them up.

So here's the rule, and it's short. Ask how many values one person can hold.

• Exactly one, always? Field.
• None, one or several? Tag.

A person lives in one country. A person is in one lifecycle stage. A person arrived from one original source. A person runs one type of business. Those are fields.

A person may have attended an event, or not. May be interested in a topic, or three. May be part of a pilot, or not. Those are tags.

That's the whole idea. Everything below is why it matters and what happens when you ignore it.

Check it with four questions

Before you settle tags vs custom fields for any fact, run it through this table. It takes ten seconds and saves you a year of drift.

If the answers pull in different directions, the fact is probably two facts. Split it.

Free guide · 21 pagesStop writing to everyone the same way.The Segmentation Playbook: tags that stay clean, segments built on fit and behaviour.Get the free guide →

Tags vs custom fields: the classic mistake of building a field out of tags

Here is how it happens. You want to mail people in Germany. There's no quick way, so you create a tag called "germany". Then "france". Then "spain".

Congratulations. You've built a country field out of tags.

It works for a week. Then it drifts. Someone moves. An import brings a country in the field and none as a tag. Another person gets "Germany" with a capital letter. Within a month the tags and the real field disagree, and you can't say which one is true.

Stage and source do the same thing. As fields, each contact has one value, and the CRM can enforce it. As tags, they multiply, drift and contradict the real field. A contact ends up tagged both "lead" and "customer", and every segment built on either is wrong.

The fix isn't discipline. It's using the right container. A field has defined values, so it can't drift. A tag has no such guard, which is why it suits the facts that really are free-form.

What tags are good at

Tags aren't the poor relation. They do a job fields can't: they record facts about a moment or an interest, and a person can collect many.

Good tags are boring. Attended the onboarding session. Requested a quote. Came from the partner referral. Each one is a fact that stays true. Nobody can argue with it next year.

Now the dangerous kind. "Hot". "Promising". "Follow up". These are feelings, not facts. They're true on the day you apply them and false soon after. Nothing removes them. And you apply them to different standards on a good evening and a tired one.

If the judgement matters, don't tag it. Express it as a rule over facts, a segment or a score, so it updates itself when the facts change. A feeling you typed in March will not update itself in June. A rule will.

A worked example, with two plain archetypes

Say you sell a course to freelancers and a done-for-you service to small studios. Same list, two very different people.

What goes in fields? Lifecycle stage, because everyone has exactly one. Original source, because everyone arrived from one place. Type of business, because freelancer or studio is one answer per contact. Country, if it changes what you send.

What goes in tags? Attended the launch webinar. Interest in the service. Part of the pilot cohort. Requested a quote. Each applies to some people and not others, and a person can carry several.

Now you can ask a real question: studios, at the lead stage, who requested a quote. Three conditions, two from fields and one from a tag, each one clean. That's a segment you can state in one sentence, which is the test covered in what is contact segmentation.

Two facts that must never be a loose tag

Some facts decide whether you may send at all. Treat those with extra care.

Consent. Whether someone agreed to receive marketing is the first filter on every marketing audience. Record it as a structured fact from the moment they arrive, and make every marketing segment respect it automatically. If it lives as a tag someone sometimes forgets to apply, you will one day mail people who never agreed.

Test contacts. Your own addresses and test runs open and click everything. They score as your most engaged contacts, which quietly flatters every report. Mark them with one consistent fact and exclude them by rule, not by memory.

Notice the pattern. In both cases the point isn't tidiness. It's that a rule needs something dependable to read. A rule built on a vague tag is only as good as your memory on the day you applied it.

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Make stage the field everything leans on

Of all your fields, one matters more than the rest. Lifecycle stage.

Every contact should sit in exactly one stage: subscriber, lead, qualified lead, opportunity or customer. The right message depends on it more than on anything else. So every other segment leans on it.

Define each stage by an event, not a feeling. A contact becomes a lead when they fill in a form, say. They become a customer when they pay. Then decide which events move a contact forward, so the stage moves when the event happens, not when you remember.

A base with accurate stages can be segmented sensibly with a handful of rules. A base with missing or stale stages can't be rescued by any number of tags.

Before you add a tag, make it earn its place

A tag costs nothing to create, which is exactly the problem. Forty tags later you can't explain half of them.

The test for a new tag is blunt: will anything ever be sent, filtered, scored or counted differently because of it? If not, it's noise. Don't create it.

If it passes, write one line saying when to apply it, and keep that line where you'll see it every time you tag. Then give it a name that fits the pattern you use for all your tags. How to shape those names is the subject of how to name CRM tags.

And decide new tags at a desk, not in the middle of a send. A tag invented at eleven at night to fix tonight's problem becomes the mystery tag you can't explain in six months.

One more thing. A tag you can't explain is worse than a tag you never made. It still matches people. It still feeds a rule. But nobody, including you, remembers what it was meant to say. So when you decide field or tag, you are also deciding who gets to trust the answer later. Pick the container that keeps the meaning visible.

Free guide · 21 pagesStop writing to everyone the same way.The Segmentation Playbook: tags that stay clean, segments built on fit and behaviour.Get the free guide →

What to do on Monday

1. Export your tag list. Read it slowly. Every tag that is secretly a country, a stage or a source gets flagged.
2. Move those facts into the real field. Fill the field from the tags, then delete the tags.
3. Convert or delete the feeling tags. Anything like "hot" becomes a rule or goes.
4. Check what depends on each tag you remove. A scoring rule or a sequence trigger may be reading it. Deleting blindly turns automations off without a single error message.

That last one catches people. Rules that depend on a tag's name keep running when the tag disappears. They report nothing and match nobody. There is no one else to notice, so you will find out weeks later when the follow-ups stop. If your segments are moving targets as well, dynamic vs static segments explains why the rule-based kind survives this better. Settle tags vs custom fields first, and every later segment gets easier to trust.

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Frequently asked questions

In tags vs custom fields, can I use a tag instead of a field to save time?

You can, and it will cost you later. A tag has no defined values and can't enforce one answer per contact, so it drifts out of sync with the real data. Spend the minute on the field.

Is lifecycle stage a tag or a field?

A field. Every contact has exactly one stage, and it should move when a defined event happens. As tags, stages pile up and contradict each other.

Is "interested in" a tag or a field?

A tag. A person can be interested in several things at once, and some people are interested in none yet. Zero or many always points to a tag.

What about tags like "hot lead"?

Avoid them. They record an opinion that expires and is applied inconsistently. Build a rule over facts, such as a segment or score, so the label updates when the facts do.

The full method, with the checklists, is in The Segmentation Playbook, a free 21-page playbook.