To answer Karina, I usually put things that I might or might not do on the Someday/Maybe list. I put things which I know I'm going to do in as a tickler to be addressed at a later date. The danger of doing the latter is that you end up just pushing things back and back and back as they pop up. Its a trap unless you actually at some point say, "OK, I've pushed this back three times. Am I going to do it or not?"
I think keeping a Someday list which is reviewed every week instead of keeping such things in ticklers is a good solution as well. I'll consider it.