For the second hand T3 I bought a Lithium Poly battery with slightly higher capacity and replaced the original one (there was a huge thread about the procedure on BrightHand at the time), and used that T3 most of the time for many years, until the battery gave out. So now the other one is the one I use - and the battery is still fine.
In the past I used the T3 for many things, with a wifi adapter it was my wireless email/network gadget, I used TomTom software for navigation, etc. But now it's just that TimeSheet application, and I'll probably continue using that for years to come.
During the day I may have to work on a number of projects, for shorter or longer periods. I have a list of those projects and work packages in TimeSheet. When the time comes to input all of that into the corporate time system TimeSheet presents me with the total sum of all work packages for each day (and other ways, if I need them).
It's extremely simple. I just can't find anything with the same easy functionality on Android or elsewhere. They seem to have a different focus, and way too many clicks to go through.
Reading Brighthand reviews was my introduction to tech lust. Terrible shame the only archived versions are text-only.