Clay bars?

Hi my paint work has seen better days but will be trying to get it to look as good as I can have a polishing machine and polish auto glym super resin polish and have time but should I clay bar it first ?

I clay bared my car for the first time recently.

The difference in "feel" was amazing, and you could easily tell where you had clayed and where you had not. Paint was much smoother.
For this reason I presume it was cleaning the surface to a very fine level.

After resin polishing it (same product you mention), the visual appearance was not noticeable at all. I dont have a polishing machine.

I would clay bar first, it lifts all sorts of rubbish, before sealing the paint.

Thanks will do be best to try and do best I can then I won't think wish I had done that first, was a bit keen to try new polisher but ended up washing it and putting cover on it, which has never been used since I bought it from Halfords a year or so ago fits well though.