Since everyone heals at a different pace it’s just a guessing game. Typical a 3 month period between shots is how pain docs work. But be cautious that steroid injections over time can hasten bone/tissue destruction. But at 80 I feel it depends on how much you’re willing to tolerate the pain before you consider surgery. As you probably are aware we heal slower as we age and considering you’ve had a long time to cause damage to your wrist recovery may take longer for you. I’m 72 and have Carpal Tunnel issues from cellphone use when still employed and afterward. I’m not keen on having more surgery unless I absolutely need it.