First off:
1) Depending where you live, we are entering the summer with High relative humidity (RH). High RH reduces the ability to develop a charge. Winter time is the worst. RH at 30 % is bad, but 20% is 10 times worse.
2) You do NOT even know you have a charge if below 500V to 1KV. You can have a 100->200V charge and NEVER know it – anyone say a CPU and Ram operate at < 1.5 V, Every component in a computer is =< 13V.
3) Rugs, wooden floors, Your idea of rubber slippers (really bad idea) – The ability to take on a charge is dependent on where the two dissimilar materials are located in a table. For example in the winter (RH =<30%) and sitting in a wooden chair the air blowing across your clothing can generate a charge very quickly. Reduced considerably BUT NOT eliminated with RH =>50%.
4) You have to touch the pins to damage a component (ie the Pins on the Ram, or the pins on the GPU) – FALSE. Explained in in 2nd link. If you are charged up say to 200V and you bring your pinky very close (NOT touching) you can still damage a component.
5) It is estimated that about 30% of DOA electronics is due to ESD damage. This does NOT include Walking wounded components that fail 3 Months to a year later, Nor does it include systems that work, just have reduced performance.
Defined:
http://en.wikipedia.org/wiki/Electrostatic_discharge
No need to read all, skip down to ESD failures, especially Walking wounded
http://www.ti.com/lit/an/ssya010/ssya010.pdf
Above is just two links out of the many out there.
My Recommendation:
A) Place Case on table
B) Install PSU, Verify PSU rocker switch is OFF, Plug PSU in (I use a Surge protected power strip) and
C) Connect Wrist strap to an UNPAINTED spot on the case.
PS wearing a $10->$15 wrist strap does NOT make a Geek out of you – Just means your smarter than the average Bear (Yogi something)
For system build-up, NO I do NOT use an ionizer, do use an ESD mat to sit components on – But that is because I have a freebie one. And Yes I’m ESD certified – Required recert every two years.