Fallout has a 150 days time limit and fallout 2, 13 years.Wait until healed often lasts 2 days.So can i use it often to heal my character?I am trying to save some stimpacks

In Fallout 2 you'll be fine (just be aware that doing it when poisoned or badly radiated might actually kill you).

In Fallout you're probably ok, but if you feel like you're running out of time then I wouldn't chance it.

You're better off resting for 24 hours, applying Doctor and First Aid to yourself three times each, and then resting for another 24 hours and doing it again. It will make the process take up a lot less ingame time (though it takes more of YOUR time obviously) but it also gives XP bonuses for successful skill usage, which can really help out in the early levels.

Fallout 2 doesn't really have a time limit, but there are still quests and events that are on relatively short timers, so if you've been given a deadline, don't dawdle.

Also to clarify, that's 3 succesful uses of both First AId and Doctor.
I'd guess you'd be mostly ok to continue after that.

Don't succumb to stimpack hoarding too easily. Or you'll finish the game with a hundred of them in the pack
and only end up using a couple of super stim packs. Just use them, that's what they're for.

Stimpacks are one of the items you will never run out. Even with very few points in pickpocket you can still steal them (save/try) and nearly every NPC has one.
So using the rest till fully healed option is a waste. Even using the skills heal or doc gives you less points than just steal from the next NPC.

Even if you have very low doctor and first aid skill and don't reload when you fail you'll still heal faster using them than by waiting.

ok guys thanks for the replies.

i only did this at the start

many of the endings are influenced by dates you enter certain places
(SPOILERS BELOW)

(for instance: youautomaticallygetabadendingfornecropolisifenteredafter110dayshavepassed)

for this i often traded my loot for stimpacks in the stores so that once i got a decent amount of cash i never used rest to heal anymore