Yes, I do restore graphite fly rods. Normally this entails removing the old line guides & replacing them. Also I normally put a new coat of finish on the rod shafts &, in extreme cases, replace or repair the cork grip &/or reel seat.
Often though, rods that have seen a lot of use may not be worth restoring. The time & money spent in working on them could be used towards a new rod. This is especially true for hard used rods. So, how can you tell if your fly rod is worth restoring, or past it's prime? Well, here are a few things to look for:
1.) Sight down each rod section & see if they are straight or have a bend to them. Now, a little bend of, say an inch or less, is perfectly fine & acceptable. Heck it's even expected on a well used rod. However, if any one of the rod sections has a bend, or curve, to it worse than that, I'd say the spine of the rod has been worn too much. Graphite rods, unlike bamboo, can't really be brought back straight again without doing damage to the material they're made of. So if you see an extreme bend in any of the rod sections, I'd say don't try to restore the rod.
2.) Next you want to look at each rod section under very good light. Here you want to look for any small cracks in the rod or in the finish coating on the rod. Small hairline cracks are a sign of stress on the rod & could be an indicator that the rod has seen better days.
3.) Examine the ferrules on the rod - particularly the female ferrules. What you don't want to see are any large cracks running around the rod at the ferrules. This is a very big sign of too much wear on the rod. Now, ferrules can be repaired, but it's usually not worth the expense to fix them unless in cases where the rod is fairly new, but just got damaged.
If you don't see any of these signs of wear on your fly rod, then it's probably worth restoring the rod. If a rod is used enough, line guides will start to wear out (as evidenced by seeing small grooves being cut into the inside of the guides), the cork may get damaged & have chunks missing, or the rod may just need a really thorough cleaning. No matter what condition issues your graphite fly rod has, if the rod shafts have not been over-stressed, than the rod should be able to be restored.