If you mean typing them in over again, yes you can but if it is a cheat like twins it will probably have no effect. others like maxmotives can be done over again.
Chat with our AI personalities
Yes you can you can also use it on another computer.
Ctrl+Shift+C
yes, you can use the sims 3 code more than once.
It depends where the code came from. There are many moped codes that are availabe which you can reuse. However, codes which came from cards/stickers can not be used twice.
Yes, of course it is.