I am curious as if to the amount of apps installed on your device cause it to slow down..
I've currently got 61 installed (includng app store, protect, and the default IM apps) and around 160MB free of my Torch 9800's app memory (over 3 GB free on card and internal storage. )
Have I gone overboard? Is there a number of apps / memory to aim for?
IMO there's no such number. What really affects performance is the number of apps constantly running and updating in the background. These are the real battery/CPU hogs. I'm ok with them taking up storage space as long as they're not killing my user experience.
If you're happy with things like your boot-up time, OS fluidity and battery life, don't worry about it.
FYI since you mentioned microSD card space: BlackBerry doesn't let you install apps there.
I'm not sure about bb's but most computers can not function the way they need to if your hd free space gets too low.
This is the case for traditional spindle hard drives... when there is little disk space left and a lot of fragmentation on the drive, the drive head performs a lot more reads and writes all over the disk just to put that file together. That has a huge performance impact in comparison to a non-fragmented drive.
This is different from flash drives though... the seek/access time is next to none so not of concern. This is because flash drives do not have drive heads... the reading/writing is almost instantaneous no matter where the data is on the drive.
In answer to the OP's question, the number of apps installed doesn't really matter (you should leave about 20MB free on the device storage though... for system activity). It's more about how many you have running in the background at any one time - this is the key factor at what will affect slowness on your device.
Y'all got a thumbs up.