Send the ring to a professional cleaning once every once in a while, and ensure that it is professionally cleaned once every six months for inlaying.
Regular maintenance is very important.
1. Put the platinum ring in a jewelry box or a soft leather pocket.
2. Take off the ring when you are doing manual work.
3. When wearing the ring, don't touch bleach or other irritating chemicals. Although chemicals will not damage platinum, they may discolor precious stones, etc.
If properly maintained, your ring should not need any repair. When you need to do some debugging. For example, when resizing, polishing or cleaning, you need to go to a professional jewelry store.
(Also applicable to other metal ornaments)