Brad - I pretty much have to do that. I set a 1.5hr timer on my phone and once it goes off I'm done. It seems to be working out good, I make notable progress and it keeps my pain to a tolerable level. I can push through and work longer but that means I'm not going to be able to doing anything for the next few days, and It's just not worth it. It's nice to have a project to tinker on