Piano keytops sometimes need repair, replacement, or a complete or complete keyboard replacement. This is not a good DIY project because you will likely change the relationship between natural and sharp heights. For an older piano with missing, broken or heavily discolored keys, a whole new set of keytops makes a prodigious improvement.
Most modern benches are bolted together, and when I come for your tuning service, I tighten it. However if your bench was built with dowel joints and the glue has given up your bench will become wobbly, dangerous and can collapse. Bench rebuilding is quick, affordable and I re-design the joinery on these benches so they will last longer than the original joinery did.