How can I get my head lights brite again with out changing the bulbs?

Both bulbs gone dim at the same time?
Check the power supply to both bulbs and the ground integrity to both bulbs...

I think its more the lens that are worn. Will changing the bulbs help?

I think its more the lens that are worn. Will changing the bulbs help?

No.

If the problem is the lense clarity, short of replacing the lamp assemblies, there are products available that can help.

One is made by Meguiar's. It's called PlastX. You will need an orbitral buffer to help speed up the process and you may find you need several applications.

Another options is from RAU Products, called Rapid Restoration System, part number 7200.
Either one works fairly well, but both require alotta elbow grease and time.

If those don't get the job done, you can remove the lamps from the vehicle and do the job manually with a very fine (1000 grit) sandpaper and lotsa water.