Part of every great friendship is an open and honest line of communication. But when a friend asks a favor—not something as simple as tying his shoe for him—but a big favor that warrants careful consideration, the lines of friendship can become blurred.

Is there such a thing as too big a favor? And whether you’re the asker or the asked, how can you navigate the situation without straining your relationship?

First of all, let’s go over the types of favors that you might want to avoid:

Financial

It’s one thing to ask a friend to spot you for a lunch, but an entirely different situation to ask them to pay this month’s rent. Money is a topic that makes many people uncomfortable, but regardless of how you predict your friend will respond, it’s best to leave financial requests to family. Or, better yet, try and handle it on your own.

Long-term contracts

You could know someone for decades and still be unaware of their level of responsibility when it comes to binding contracts. Never ask a friend to co-sign for you on big purchases like a car, or on loans. It’s a recipe for disaster.

A place to stay (indefinitely)

Knowing you always have a place to crash if need be is one of the biggest benefits of friendship. You shouldn’t necessarily feel uncomfortable asking to spend the night—that is, a few nights. But if you predict your short-term stay will turn into them putting you up indefinitely, try and make other, more permanent arrangements.

Something you never offer to help with

If you’re allergic to peanuts, and your friend asks you to take their shift at the peanut butter factory—by all means, decline. But if you know your friend really hates moving and you’ve helped them in their move multiple times, don’t feel guilty asking for a hand.

This is not an exhaustive list of the favors you shouldn’t ask, but it does cover some of the basics. When considering asking a friend for help, use your best judgement. Is it a favor you wouldn’t want to do? Would it be burdensome? If so, reevaluate.

Now, if you find yourself feeling uncomfortable because of a favor asked of you, there are a few different ways you can proceed:

Tell them directly.

If this is a good friend, you shouldn’t have to beat around the bush about your feelings. Explain why you think this favor is asking too much, and that, while you might like to help, it’s simply too much for you to take on.

Offer an alternative.

If only a portion of the favor is too much for you, try offering to help with anything that might alleviate some of the pressure on your friend. For example, if you’re asked to take a friend to the airport but it would be more convenient to pick them up upon their return, offer the latter. You might not be able to help them in the way they asked, but in other ways.

The next time you’re about to ask a favor you feel uncomfortable about, or you’re asked a favor that you’re unable to accept, think about these solutions and tips.