No ..... Certainly pack the extra undies .... They don't count asextra clothes is what I meant ...... Good hygiene is more a health issue than a smell problem.
Ray Jardine, in his book on ultalight hiking, recommends carrying a lightweight wash tub ( cut off bottom of a milk jug) to wash your spare socks and undies daily .... Rotate a clean pair on when you wash up every day or evening, then wash out your extras with a couple of drops of dr. Bronners and hang your stuff up to dry under your tarp or on your pack, depending on when you can.
Clean socks and undies are worth their weight in gold on a long hike.
Another tip that I use, is I hang up my tarp somewhere away from the shelter like a shower curtain. I like to use plastic soda bottles, or at least one bottle, for water, then take an extra cap and drill a small hole in the middle of the extra cap.
Warm up some water, say with alcohol that is left in your stove after your dinner water boils, and fill up the 20 oz bottle .... Put on the holy cap ( I had to say it Uncle MJM ), step behind your semi secluded shower curtain, and have a quick impromptu shower with a few drops of dr. Bronners and a bandana as a wash cloth. If your hair isn't too long you'll have enough water to wash your hair too .... Dr. Bronners washes out quick and easy with no residue.
Put on your clean undies and your hiking clothes, and you'll sleep SO much better you won't believe it.
Then wash the dirties again and repeat the next day or at least every other day.
Then every 4th day you'll hit a place to have a real shower and wash your hiking clothes.
Me, I typically carry extra undies, socks and a spare shirt. For undies I like spandex compression
shorts because the almost completely eliminate chafing, but can also double as shorts in a pinch, especially with a long tee shirt. That facilitates washing my parts and dirty shirt every 4 days.
One more trick ..... Cut a window on the side of an empty soda can, flatten part of the domed bottom, add a short candle, and you have the world's lightest directional candle lantern.
What else can we help with? The things we miss on the trail are typically the last thing you'd think of at home .....
Drop us a note on this forum when you can and make sure you let us know if you are missing anything. We hikers stick together.