in a perfect world get a big one. in the old days, before there were good electronic measuring devices, they used to tell you raise it all the way up, then back off till the
windows don't have condensation on them. that may be overdoing it, but remember humidity holds heat. the building doesn't get cold as quickly, feels more comfortable and protects your equipment.
the electronic stuff is in danger if you are walking on carpet, mostly
every time you feel a shock, it is a tiny discharge of over 2000 volts (no wonder it is so destructive)