Separate sleeping clothes – yeah or nay

In a prefect world, your sleep clothing should be a coordinated part of your insulation system and sleep system, available for use whenever needed. I would not carry clothing to be reserved only for sleep.

Depending on the weather, I would normally wear a long sleeve base layer and have a fleece mid-layer and puffy layer for camp. Unless it is full-on hot summer weather I would also have light to medium weight long johns that I would wear under rain gear and/or for sleep. If it is colder than my sleep system can deliver, I would wear everything to stay warm, including rain gear. That is rare.

As far as staying clean, sure, make the effort, but don't be afraid of a little dirt. I take a sponge bath at the end of the day whenever possible. If my base layer top is too sweaty, I can always wear my fleece mid layer for sleep. I do carry spare socks and would wear the driest, cleanest pair for sleep, or both if really cold. I wouldn't be adverse to wearing gloves and hat as well.

I don't wear my outer layer to bed. That keeps most if not all of the dirt out.

Section hikes and winter, spring, and fall short UL trips I keep a pair of either merino wool or synth base layers (depending how cold it is) in a water resistant stuff sack (silnylon) which is carried inside of a seam sealed backpack. Put on the base layers before bed, and any other needed layers from clothing worn based on how cold it is. I will wear the base layers under my clothing worn in the morning and either change as I break camp/pack or on the trail as the day warms up.

Summer SUL/XUL overnight trips then no. Sleep in clothing worn if needed. I have only done overnight trips for SUL/XUL, so I have not been that dirty, thus no big deal.

In the future I might do a SUL section hike, though not sure if I would take base layer or not–it would depend on the conditions. With really warm conditions, I could get away with using just a fabric bag liner (I have a cotton and a nylon one) as a sleeping bag, in which case you can just wash it afterwards.

Never been on a thru hike, but plan on it one day–in which case I would most def take a base layer.

As part of my minimal clothing kit is a lightweight set of upper and lower base layers, for layering if things are chilly. I also tend to use them as (relatively) clean garments to wear in the sleeping bag to help keep down bag grunginess. Also lets me take a lighter weight bag and lighter weight sweater, etc.

I will bring an extra sleep layer for two types of conditions: lots of rain, where I know I can't stay dry during the day; and really humid conditions, which amount to the same thing in effect. In either situation a dry layer is well worth the extra weight.