how do I keep leafy greens fresher longer?

I usually wash them and then wrap them in a paper towel in the fridge. This seems to keep them fresh.

If you buy live lettuce (like butter lettuce with the roots still there), then it will last quite a long time.

If you buy them already tricked out in plastic bags, you know, Tanimura & Antle or those other organic types, for some reason they seem to last forever. Maybe they irradiate them.
It doesn’t make any sense.
Romaine also lasts longer than all those little baby greens..