Too much weight on anything, especially older joints just makes for/exacerbates problems. Keep up the TLC and attend to the finer points, like teeth and feet and the mins and vits and look forward to a lovely summer with him.
annret: after seeing the vet and farrier, we all came to the conclusion that, the work he does (hacking, low-level dressage) he does not need remedial farriery, and at his age, it's not worth it. He has hadit long before i got him, and according to vet, he is fairly sound with it. i can cause a spasm occaisionally, but he sees a physio for that. If he was younger or doing more work/jumping, i'd have it sorted.