The 7 Biggest Mistakes People Make in Casual Agreements

Casual agreements fail for predictable reasons. Not because the people involved are bad at relationships, but because they skip steps that seem unnecessary until they aren't. After looking at hundreds of arrangement stories and common patterns, these are the seven mistakes that show up again and again.

Knowing them upfront saves you from learning them the hard way.

Mistake #1: Keeping Everything Verbal

"We talked about it" is not the same as "we agreed to it." Memory is unreliable. Two people can leave the same conversation with genuinely different recollections of what was said. One person remembers agreeing to meetups twice a month; the other remembers twice a week. Both are certain they're right.

The fix: Write it down. It doesn't need to be formal or legal. A shared note, a text summary, or a simple document covers the basics. What matters is that both people have the same reference point.

Many people hesitate to put things in writing because it feels "too serious" for something casual. But the alternative — perpetual ambiguity — is what kills arrangements. Read more about why writing things down matters even when it's not legally binding.

Mistake #2: Skipping the Exit Plan

Everyone is happy to discuss how the arrangement starts. Nobody wants to discuss how it ends. This is human nature — talking about endings feels pessimistic when you're excited about a beginning.

But arrangements end. All of them. And the ones without an exit plan end messily.

At minimum, agree on:

How either person can end the arrangement
How much notice to give
What happens to property and finances afterward
What the post-arrangement boundaries look like

This isn't pessimism. It's preparation. Read our full article on Ignoring the Exit Plan for a deeper dive.

Mistake #3: Assuming Instead of Asking

This one deserves its own full article — and it has one: Assuming Instead of Asking. But the summary is this: every assumption you make about the arrangement is a ticking time bomb.

Common assumptions:

"We're exclusive" (when it was never discussed)
"They'll increase the allowance over time" (when it was never promised)
"We'll see each other more often eventually" (when frequency was never agreed upon)
"They understand what I meant" (when you were vague)

Every assumption is a conversation you didn't have. Have the conversation.

Mistake #4: Ignoring Power Imbalances

Most casual arrangements involve some kind of power asymmetry — age, wealth, experience, social status. That's not automatically a problem, but ignoring it is.

The person with more power has a responsibility to ensure the other person feels free to:

Negotiate terms
Say no to specific requests
Raise concerns without fear of financial consequences
End the arrangement if it's not working

If one person feels they can't speak honestly because the other controls the money, the arrangement isn't casual — it's coercive. Even if that's not the intention, the effect is the same.

The fix: Actively create space for honesty. Ask questions like "Is there anything about our arrangement you'd change?" and actually listen to the answer. Schedule regular check-ins where both people have equal voice.

Mistake #5: Not Discussing Boundaries Around Other People

Who else knows about the arrangement? Who's allowed to know? What happens if a friend, family member, or colleague finds out?

These questions feel awkward, but ignoring them leads to scenarios like:

One person mentions the arrangement to a friend, who tells someone else, who tells someone who shouldn't know
Partners or spouses discover the arrangement through carelessness
A friend gives unsolicited (and often bad) advice that poisons the dynamic

Agree on discretion levels upfront. A confidentiality conversation is a form of mutual respect, not paranoia.

Mistake #6: Confusing Casual with Careless

"Casual" describes the structure of the arrangement — it means both people have agreed to certain boundaries around commitment, exclusivity, or emotional involvement. It does not mean:

You can treat the other person carelessly
Promises don't matter
You can cancel without consequences
The other person's feelings are irrelevant
Communication is optional

Casual arrangements require more intentional communication than traditional relationships, not less. In a relationship, shared context fills in the gaps. In an arrangement, if you don't say it explicitly, it doesn't exist.

Mistake #7: Using Someone Else's Template Without Customizing It

Templates and guides (including this one) are starting points, not finish lines. Copying a generic arrangement template and filling in your names without thoughtful discussion about what works for your specific situation is a recipe for mismatched expectations.

Every arrangement is unique because every pair of people is unique. What works for someone on the internet may be completely wrong for you. Read more in Why Copy-Paste Templates Backfire.

The fix: Use templates for inspiration and structure, but customize every single term through genuine conversation. Both people should have input. Both people should feel heard.

A Quick Self-Assessment

Before you start (or continue) a casual arrangement, ask yourself:

Are the core terms written down and agreed upon?
Do we have an exit plan?
Have I stated my expectations clearly, or am I relying on assumptions?
Does the other person feel genuinely free to negotiate and disagree?
Have we discussed who can know about the arrangement?
Am I treating "casual" as a license to be careless?
Did we discuss and customize our terms together, or did one person dictate them?

If you checked fewer than five, you have some conversations to schedule. Start with a check-in.

The Bottom Line

These mistakes are common because they're easy to make. The good news is they're also easy to prevent — all it takes is a little upfront honesty and a willingness to have conversations that feel slightly uncomfortable in the moment but save enormous pain later.

For more on what can go wrong and how to prevent it, explore our Common Pitfalls hub.