So, I've got a once-coveted Blackberry Pearl, which I love to death. One of the strange things I've discovered though, is that they are susceptible to their own little problems and bugs.
On this page, please find my fixes for the occaisional annoyances of the Blackberry 8100. Please note, these tricks may work on other models, however YMMV.
Within this section are the fixes and/or work arounds I've found for the bugs that seem to crop up.
Call Logs/Email/Etc Disappear
After having my Blackberry for about 3 months now, my call logs started to clear out (read, there would never be more than 2 calls in the log), and emails started to disappear. The emails didn't bother me so much, as pretty much everything that goes to my phone, is also being sent to my laptop. The call logs, however, were another matter.
Short Term Solution
I found out that, much like Windows, the Blackberry is not impervious to memory leaks in the software that's running. If you never restart your phone, as I don't, your Blackberry can run out of memory. When this occurs, the first two things to go are the call log and email. The quick fix is to pull the battery or just restart your phone.
Long Term Solution
Update: T-Mobile has release an updated software pack for the Blackberry Pearl, which includes a fix for this bug. You can view T-Mobile updates for the blackberry, and instructions on how to upgrade you phone at http://www.t-mobile.com/bbupgrade/
A longer-term solution is to program your phone to automatically restart at a specified time. To do this, make sure you do not have a PIN set on your SIM card (for those carriers that use them). You can disable the PIN setting by going to Menu->Options->Advanced Options->SIM Card When there, you should see your SIM ID number, as well as your phone number. Pressing the MENU key again should display an option to Disable Security. Your Blackberry will ask for your PIN before actually disabling the feature on your SIM card.
Once you've got security turned off on your PIN, you can set up a schedule to restart your phone. Get to the correct menu by going to Menu->Options->Auto On/Off. In my case, I programmed my phone to turn off every weekend and every weekday at 03:00, and to turn back on at 03:01.
Please Note: You do not have to turn off SIM security to make this trick work. What will happen if security is enabled, however, is your phone will await the entry of your SIM PIN before allowing the phone to function. In my case, I don't want to miss calls or email alerts.