Do you have a bed liner?

I think spray on liners are ideal. They don't cause any issues with rust like the mats or plastic liners can, they make the bed less slippery and they wear a lot better than the factory paint. I don't think I'll ever own a truck without a spray in liner. My dad is a retired farmer and never had anything done to his now 20 year old Super Duty. His bed is essentially bare metal at this point but it's totally functional, so you don't necessarily need any kind of liner.

Now if you have a Ford with an aluminum bed a mat or drop in liner may not be a bad idea. There shouldn't be rust issues because aluminum, and they don't seem to be quite as durable so the extra layer of protection may be helpful.