I personally have found System Restore to occasionally save my @ss when something gets messed up -- and am too lazy to keep turning it on and off -- so I set it to use 3% of my SSD (about 1.79GB). It seems to be an acceptable compromise. By default, Windows sets a much larger % of disk space, but then you just end up with lots of old restore points.
i3-3225, 3.3GHz w/stock HSF, GigaByte H77M-D3H | 4x4GB Kingston RAM = 16GB
no graphic card (IGP HD4000) | Samsung 840 EVO 250GB | 2TB WD Green
Silverstone Temjin TJ-08E | CoolerMaster eXtreme Power Plus 460W | Win 10 Pro 64-bit
Dell U2312HM 23" LCD (Also have Lenovo Yoga 2 Pro & Microsoft Surface 3)
Location: Thailand (several hours south of Bangkok)