I acquired two flight suits (cotton, not Nomex) when I got my PPL (bought one, was given the other- ex mil) 20 years ago.
I wore one once but found it too restrictive and hot and have never worn either again.
I do however always wear long sleeved non-synthetic shirts & trousers, avoid shorts and open sandals whatever the heat, and always wear the ex RAF thin white leather gloves and replace them (I have to buy them now!) whenever the thumb pokes through.(I found the US Nomex gauntlets too thick/insensitive for cockpit use).
That combination takes care of my perception of risk when flying my P28R and I figure in a fire might just protect my fingers long enough to get back down on the ground before I crisp up.
Cusco