Pro tip: Always accept offers
This might seem counter intuitive or dishonest. But if you go the other route I guarantee that you are going to screw yourself over and feel stupid. Once you get that first offer, another one might be right around the corner. Your current job might do something surprising like switch your projects and/or give you more salary because it's raise time. Situations I've been in before.
Everything is negotiated in effect before you even have your first phone screen. The salary, benefits, vacation time, all of that is baked in. Once you get the job offer make sure you note the expiration time. The employer is looking at that date and doesn't want to move it.
If you already have a better offer, or you changed your mind, just decline it. It sucks to decline opportunities but it at least resolves the issue so you can focus on your new choices in front of you. If not though, accept the offer. Proceed with whatever they need to get you in on the first day. Your new deadline becomes, the first day of work.
Now this might seem really dishonest but hear me out. The employer wants to get this resolved. They feel that they have resolved it. If they have someone that isn't sure about something, or wants more money, or whatever the reason is they're going to feel the hesitation and as soon as that expiration date expires they are going to dump your ass and go for their #2 pick.
And if that happens you are going to feel bummed, like a piece of nice candy just got stolen from your pocket. They are looking out for themselves and their company, isn't personal they just need someone to fill the position. Either way this goes if you back out of the offer, don't accept the offer, or back out later after you are burning a bridge. Trust me on this one. It doesn't matter when it happens, what does matter is that you aren't screwing yourself over in the meantime.
And look, 9/10 you'll actually want to go through with the offer. That's great! At least you still have it because you didn't act like a wishy washy candidate that was going to flake at any moment. :D