Wearing layers in your sleeping bag....

[6mm Remington]

I have been wearing loose fitting boxer shorts, a light base layer shirt, a stocking cap, and medium weight wool socks on the feet. If my head and feet stay warm, it seems to make a huge difference.

 

[Mike7]

My preferred setup for cold or warm weather is almost the same and then I just adjust how much of my body is in the sleeping bag depending upon the temperature.

Mike, for me, a beanie (fleece Arctic Shield version) definitely helps increase comfort in cold weather, as does thick dry merino wool socks seemingly. Otherwise, I don't wear much of anything as I always have my Sea to Summit liner in my bag. I think with a larger bag or a stretchable bag like Montbell, you might find that a puffy jacket/pants actually makes you warmer also, if you really need it because of extreme cold...but I can't say that I've comparatively tested this. My wife sleeps colder than me and she will sometimes keep her puffy jacket on in her Montbell bag in the winter and it seems to work for her.

I can sleep on snow to below 15 deg quite comfortably in my Montbell 30 deg bag with a Sea to Summit liner, merino socks, beanie cap, merino boxer shorts, and with a full length mummy BA IAC inflatable pad on top of a short Ridgerest closed cell foam pad.

 

[fillthefreezer]

I like to use my bag mostly unzipped a lot, would i be able to use a liner like that?
forgive me, I've never used one before but like the idea as i don't like sticking to my bag

 

[Mike7]

Oops, I forgot that for <15 degrees I have also had my 7-8 oz Montbell sleeping bag cover/bivy over my sleeping bag.

Ya, I use the liner just you mention during archery elk on warm nights...just sleep in the liner with the bag mostly as a 1/2 blanket on warm nights. I like having the long (?6 oz) Sea to Summit silk-mix material liner that is like very thin t-shirt type material. It keeps you from sticking to your sleeping bag or inflatable pad, but is still roomy enough to move around in and spread out some. The other big advantage other than comfort is that I never have to wash my down sleeping bag.