"I just need a little more time" can be a reasonable request. It can also leave you dating someone for months without knowing whether you want the same future. The calendar alone cannot tell you which situation you are in.
There is no universal number of weeks you should wait for someone to commit. A more useful question is whether waiting involves a shared direction, honest conversations, and an arrangement you can comfortably choose today.
What would actually change if you waited?
Imagine two people asking for more time. One says they enjoy dating you, want a committed relationship eventually, and would like a few more dates before deciding about exclusivity. They keep making plans and are willing to revisit the conversation.
The other says "maybe someday," avoids explaining what they want, and becomes irritated whenever you ask. Another month passes, but the conversation stays exactly the same.
Neither example lets you predict the outcome. The difference is that the first person gives you something concrete to consider. In the second, you are being asked to invest in a possibility without much information.
Before deciding how long to wait, have the "what are we" conversation. Be clear about whether you mean exclusivity, a relationship label, or making more consistent plans. You may discover that you have been waiting for an agreement they never intended to make.
Set a review point, not a secret test
You can give yourself a date to reconsider without turning it into an ultimatum. Choose a point that fits your circumstances, then communicate the next step:
"I'm comfortable continuing to get to know each other for now. Could we talk again in a few weeks about whether we want an exclusive relationship?"
That is an example, not a recommended deadline for everyone. What matters is that you both understand the question. A private countdown followed by an unexpected demand does not give either person much room for an honest discussion.
Until you have agreed otherwise, do not assume you are exclusive. Keep your own friendships, routines, and plans rather than organizing your life around a hoped-for answer.
You do not have to wait until they decide
Ask yourself what the current arrangement costs you. Are you choosing it freely, or accepting it because leaving feels harder? Would you still want this relationship if it stayed the same?
If the uncertainty has become the defining feature of your connection, these signs of a situationship may help you describe what is happening.
Someone can care about you and still be unavailable for the relationship you want. You do not need to prove that their reasons are dishonest before deciding the arrangement is wrong for you.
When your review point arrives, consider their answer and their behavior together. Continue if the arrangement still works for you. Step back if it does not. The purpose of a boundary is to guide your own choices, not to make another person choose commitment.