Yep, I run the bare minimum really, and I'm guessing that iFile counts as an app?
Even so mine doesn't take long to respring, but them again I'm only using iFile and NoAccSplash. I'm not really a fan of all of those other themes and effects that you on those 'top 10 Cydia tweaks' type sites.
Do you know if different models have different respring times?
Imagine a 4s would be quite a bit faster than a 3GS?
iFile does not add a MobileSubstrate so it runs like an app so your fine with that.
Yes, different models have different times as the processor does come into it.
The stuff that really slows it down is tweaks and addons for SIRI as these are running constantly, even when the phone is locked, eating up your RAM, and running constant processes in the background. "Hands Free Control" is one of the worst tweaks ive encountered. When using it, my memory would go from 250mb~ to 120mb~ and the phone would lag. Avoid like the plague! You have to remember these are new tweaks which really haven't been fine tuned yet. They will get better as time goes on and newer versions come out.
SBSettings is another one that is hungry. You can minimise the usage by cutting down on the number of toggles.
I would really recommend doing a lot of changes to the iOS rather than using an app to do it. Cut down reliance on apps as much as possible (when customising) and only have what you use.
Another thing ive found is that when you install an app from a .deb file is does not have the same affect as installing directly from a Cydia repo. An example of this is that i recently installed Copics from a deb file and noticed my phone seamed to lag a little. I removed it, removed all traces of it using iFile and then installed directly from Cydia repo. Lag is gone.
PS. When you uninstall an app from Cydia, it does not always remove all traces! The settings file and the MobileSubstrate (MS) generally get left behind. Use
Springtomise to delete the settings file and turn off the MS.
Think of these MS as an Apple service such as Location services. If it runs all the time it consumes memory, power and battery.
LockInfo is one of my favourite Cydia addons. It also isn't a resource hog. The reason for this is because the Author is a great programmer and has fine tuned his skill over several years. This is one of the reasons i pay for it!