You'll start feeling it in about a hour, and they last from 8-12 hours.
I thought you were going to stop Runz? Now you're trying stronger stuff, be careful.
I did stop for a long time (maybe a month or so?).... and then I found oxy's which are kinda rare around here and they were really cheap so I bought some, but I dont really like them. idk.. I also got a ton of watsons too... but I might just get rid of them.