I'm on timespan, 180 mg in the morning, and another 180 mg in the evening. I find that the literature on daytime timespan is pretty accurate: it fluctuates a LOT during the day. Sometimes I'll feel fully medicated, and then be unable to walk for a half hour, and then be right back to nearly full strength.

That said, I seemed to be fairly weird with the instant Mestinon. It would take over an hour for me to start feeling anything, get only an hour or two of results, and then have to wait awhile to take my next dose. And since it would make me so sick to take it without a full meal, I really couldn't take it as often as I needed to. That's why I got put on the Timespan.

Overall, I spend more of my day medicated while on the Timespan than the instant, but it's a lot less predictable.