I know, it's not about drums. But it is, humidity, temperature are contributing factors to vintage drum health.
As a professional for 20 something years, let me give a few bits of wisdom.
#1 Number one, keep your system clean!! A five dollar filter changed every 6 months makes a big difference, trust me. I can't count the number of homes and businesses I've been to that spent more than a couple of hundred dollars for me to clean what could of been stopped by a filter.
#2 If it isn't working like it was, maybe there's something wrong. I guarantee if you continue to run it when it's not performing correctly, you're gonna make it worse.
#3 Be realistic, it's a machine. They break, all machines will eventually.
#4 When it's humid outside, that sucker's gonna run a lot. The unit first has to dispell the humidity, then it can drop the temperature. Out here in California, people freak out when the humidity goes up and there unit runs continuously.
#5 Big one, rule of thumb, above 100 outside, if you're 20 degrees cooler inside, you're doing good, any lower, you're doing real good
#6 Keep it clean and it will save on operating costs, keep you comfortable, and best of all keep the humidity down and keep those drums happy.
Lastly, the best piece of advice. I recommend using a company that pays their employees by the hour, not by the job. Why? Because more times than not, the person that makes money by piecework or commision is going to give you something that you really didn't need.
Have a good summer, I'll be working my butt off for "the man"
Gary