battery life - Should I keep my Android tablets' power off or leave them on standby mode?

I have two tablets: Allwinner A10 single-core 10 inches (old one) and Allwinner A31 quad-core 9.7 inches (new one).

I notice that sometimes when not using the tablet's standby mode, the battery drain is 20 to 30 percent, there's also a little heat near the battery on the back of the tablet, and it sometimes becomes slow so I have to restart anyway. (I install lots of programs, software, browsers, readers, games, movie/music players. Recently the tablets are filled with Android applications.)

A couple of questions:

1. 
   
   

   Should I keep my Android tablets power off or leave them on standby mode? Which option is better?

   
   


2. 
   

   Will turning the tablet off at night when not using it increase the tablet's life?

   
   


3. 
   

   Will it increase the battery life in terms of charge/discharge cycles if the tablet is left off when not used? So it increases battery longevity for years?

   
   


4. 
   

   Will it also increase the life of the memory card and flash memory (as they are dependent on read/write cycles)? Something might be getting written to them by some background programs if the tablet is on standby?

   
   
   


5. 
   

   Will it also increase the MTBF (mean time between failure) and longevity of the ARM processor and other electronic chip components, etc., of the tablets?