It is advisable, but read the instructions and know what you are doing. I have built PC's both with and without one. It depends on the environment your building in. If you have carpet and other static generators nearby, a grounded wrist strap and anti-static mat are a good prevention.
I have built a few computers aswell and I have never used this wristband
when people see me not using this they freak out and think I dont know about it but just touch the metal case and you will loose your static
Im sure one of these days I will fry something... Ill get a wristband later on once I fry something
Just some info:
1) May ESD related damage is NOT an immediat failure. Often it results in degraded performance, or pre-mature failure (refered to as "walking Wonded"). When a component fails 3 months later - Most blame the Manuf when infact they caused the damage. It cost something like $30K to check an IC for ESD damage, reason manuf do NOT check or and simply replace - Even a High end GPU, or CPU, the relacement cost to the company makes it cheaper to just honor the warranty.
2) You can have several hundred volts charge on your body and NEVER know it. Anybody say that CPUs and Ram operate are 1->1.5 V
3) Myth. You have to touch a pin to cause the damage. You can damage a IC just by bring your finger very close to a IC. This is due to the Electrostatic field surrounding a Charge.
4) The ability to generate a charge is much worst during the Winter monthes when Relative Humidity (RH) is very low. 20% is 10 times worst than 30%. 30 % is consdered the trip point of requiriing extra precautions (in addition to just requiring a wrist strap.
5) Touching the case. This is fine if A) the case is grounded (ie PSU pluged in and PSU rocker switch is off), B) surface must be unpainted, and C) You keep your one hand on the case while doing the work. Remove your hnd and you can very quicky generate ESD ust by twisting your body (More so @ <30% RH - not so bad summer time when RH generally >60%.
6) Carpets, yes worse than wooden floor. But abilty to generate a charge is placement of the two dissemilar materials on a chart. Just pulling tape off of a tape roll can generate several hundred volt, even when RH is >50%.
Take a look at http://hardforum.com/showthread.php?t=812518
Scoot down to the “In response to a guy who said he’s never damaged anything due to ESD…..”
Ends with “Either way, all us tech’s hate the “dorkstrap”….. since its cheap insurance”
Really think that all the returns that are labeled DOA and Only worked for a Month or two are from Manuf defects - Some Yes.
I could go on, but not much point.i