I was thinking about this but an electronics engineer I know has told me that it's a bad idea and that you should replace like for like; ie replace electrolytics with electrolytics and solid state with solid state. Replacing electrolytics with tantalum, for example is potentially a bad idea. Their failure characteristics are quite different. An electrolytic will fail gradually and tend to open-ircuit, a tantalum will tend to fail suddenly and closed-circuit. The latter is not a good prospect.
