On Windows, in time, the OS becomes bloated and buggy. After installing and uninstalling various apps, once a year, I usually format the drive and reinstall everything. Main cause of this are the apps and the trash they leave behind. Registry entries, dlls, files in the system folder, god knows what. While this is not a big problem on a PC, on a phone it's not as simple. You'd need to reflash the device to start over. I try a lot of apps on my phone. Install, uninstall, install again. I like to try new things, for example, when the Fox News app came out, I installed it just to try it, then removed it as it was wasting valuable memory space (waiting on 2.2) The question is: will trying out apps eventually bog down my phone? Do apps leave some trash behind? - and I'm not talking about files on the SD card (these can easily be recognized and removed with a file browser). I'm talking about something in the "system" part, like, in the ROM or in the Android OS files (not sure if this is possible, just asking) I know bad apps can slow down your phone or waste battery life, but does removing them remove the negative side-effects as well? And am I free to try new apps without worrying that the Android OS will slow down as a result of numerous installs/uninstalls? I like to try new apps, but I feel bad whenever I install something.