I disagree with dropping the free trial just because you have a free version.
It's always a nice gesture to let users see paid plans before any money is exchanged.
There are many reasons for this, but the most important one is letting the user test drive your software with no limitations so they can evaluate if their needs will be fulfilled.
It depends on the day. I use multiple timers to track my time, and the correlation goes like this >
The more timers I have correlates to more multi-tasking, and when I multi-task, I usually deflate quicker, so I end up losing steam at around the 6th hour. It takes some coffee to finish up the last two.
On the flip side if I'm working on one or two projects I can go 8hrs with no problems.
http://www.myintervals.com/