You may be surprised to learn that washing high-tech garments is actually recommended and maintains their performance. This is true of down gear as well, but see below on down care. In fact if you neglect washing, you may find gear permanently harmed.
The guideline is to follow instructions. Almost all garments have care tags -- they may even be mandated. They are certainly on my Arcteryx and Patagonia items that I care a lot about. There is an official system of hieroglyphic like symbols that you will never decipher using intuition and common sense. You need something like this:
Both bleach and dry-cleaning are universally prohibited.My Arcteryx Atom vest indicates that you should machine wash it cold using a genle cycle. My machine is a front loader, which is more gentle on any cycle. Then you should tumble it dry.
My Cloudveil softshell (Scholler fabric) indicates that it should be machine washed cold and gentle, then hung to dry (not tumbled).
Typical Gore-tex shells indicate a machine wash cold and gentle followed by a tumble dry with low heat.
Gore-tex garments are definitely harmed by skin oils and such, so they benefit from being kept clean. Also the outer nylong shell on garments like these has a DWR coating that is essential to garment performance and needs to be restored and replenished.
It only makes sense to take proper care of garments that you invested a lot of money in. I long held the view that I was wise to avoid laundering these high-tech garments, but that is absolutely not true.
Wool may (or may not) require special care and detergents. Check the care label. My Merino wool "darn tuff" socks go through the wash with all my other clothes, but not the dryer. I let them (and almost all my socks) air dry to avoid shrinkage.
Tom's backpacking pages / tom@mmto.org