Volvo does not officially recommend ever changing ATF for your car in writing, not listed in any maintenance schedule BUT those who repair the cars for a living know otherwise. IMHO, it should be flushed at least every 50K miles and if it were my car, I'd do it more often.
There isn't a high failure rate compared to most other cars, especially if you had another type car and also never changed its ATF.
90K miles on a '95 car with original ATF (assuming?) wouldn't be unusual but for future referance with your next trans, do have its fluid flashed occasionally as that will help it last longer than 90K or so.