Training on "other bikes" (road, mountain, track)

[adal]

I do most of my training and racing on a triathlon bike. But I also like to use my MTB, train on the track in winter and use my roadbike exclusively from the last race until camp in march.

From April to Oktober I use the TT bike 90% of the time, the road bike for an occasional race or recovery ride and the MTB for mental recovery in the forest (to recover from work, not from training).

Whats yor thought for the right way of using multiple bikes (road, time trial, track (with a track available) and MTB)?