[Yugocean]

You will have many shirts that are not wearable outside, so it is better to use them in the winter than to sell them for pennies. You can wear old shirts inside your sweater or jacket.

People will see the sweater from the outside, not the shirt from the inside.
This will also make use of your old shirt, and the unnecessary use of a shirt that can be worn outside will increase its life.

[oldbuddy]

Most days I still wear old T-shirts I got as free handouts at computer shows 20 years ago. I have hundreds of them still in good shape.

[darkuszerx]

Yes, when I have clothes that I don't think are fit for me to wear outside the house, I will wear them only in the house instead of selling them for a few pennies.

[vbludwig]

I always wear my old clothes in the winter because I don't need to buy new ones if I don't really need them.

[Yugocean]

Most days I still wear old T-shirts I got as free handouts at computer shows 20 years ago. I have hundreds of them still in good shape.

Very old shirts are alwyas in good shape, they were made by real materials, not synthetic, they will work even outside.