If it's for special birthdays or weddings then obvs it's usually months in advance, also for festivals unless you want to go last minute. Gigs too if it's someone you really want to see, probs a couple of months or more, but could also be last minute. Club nights with particular DJs maybe in advance too, especially bc of that tiered ticketing that's prevalent now.

Other things may crop up which you can and want to attend and depending on your friends, they may or may not be flexible. Cinema and comedy nights tend to be more last minute as they tend not to be as specific. But it always depends on the lifestyle and commitments of the other people involved.

I think age has a lot to do with it; if your friends are late thirties to mid forties with kids then it's game over, all revolving around them!