One of the most common early relationship experiences is deciding when to say “I love you”—that is, of course, after you figure out you are in fact in love with your partner. It’s not just timing that’s an emotional struggle. There’s where to say it, how soon is too soon, and what to do if the other person doesn’t say it back…ever.

Yep, dropping the L-bomb is a tricky romantic milestone. To get clarity on the exact right time and how you’ll know you’re ready and really feeling it, we reached out to relationship experts. Here are the three guidelines they advise.

Consider putting it off at least 3 months

Of course, every relationship is different. If you truly believe you’re in love by the second date and your heart is about ready to thump out of your chest if you don’t share the realization, then, by all means, go for it.

But more often than not, even if you think you’re in love, consider waiting. That’s because the progression of love takes time, at least three months, Rebekah Montgomery, PhD, a therapist in private practice in Washington, DC, tells Health. If you think you feel it beforehand, it’s probably lust, infatuation, idealization, or chemistry.

This is because romantic love has a lot to do with amassed experiences with the person you’re dating. “How deeply do you know them—like, really know them?” Montgomery says. “You can fall in love with someone when things are going well and you’re having fun, but how about during stressful times, extended periods of time in each other’s company, travelling together, or when one of you is sick, vulnerable, or not at your best?”

Wait until you won’t care if they don’t say it back

This one is a biggie. “The most critical aspect of deciding when to say ‘I love you’ is waiting until you feel comfortable with whatever the outcome is,” Montgomery says. “You want to feel good sharing how you feel, even if your partner isn’t quite ready to reciprocate.”

Montgomery emphasizes that you shouldn’t panic if they don’t return those three little words right away. “In fact, it’s even good to let the other person know you don’t need them to say it back,” she says. “It’s unrealistic to expect that two different people would experience the same exact emotions with the same exact timing.” In a relationship, you will be ready for things at different times: the first kiss, sex, moving in together, etc. “It’s about navigating the natural differences in timing,” she adds.

Also, a person’s definition of love may change with time and age, or over the course of a single relationship. “Infatuation, or the period of time in which you are totally absorbed in another person—see the world through rose-coloured glasses, potentially ignore red flags—has been shown to last up to two years,” she says. “It’s not that a person needs to wait two years to say ‘I love you,’ but the ‘I love you’ can communicate different things, and the meaning behind it will evolve.”

Just don’t worry if they don’t say it back right away. Unless your partner explains that they don’t see those feelings coming at all, it’s more important that they’re putting forth the effort to grow the relationship and they take their time to say those three little words. An honest, sincere “I love you” from someone you’re sure you love is worth the wait.