Q.Miniature roses
Should potted mini roses be repotted each spring before bringing out from garage?

If the pot is small in comparison to how big the rosebush gets, then yes. Otherwise the root system can start to grow in the shape of the container and become root bound leading to its death. Some mini roses are planted in a good sized pot and can stay there for two to three years. If you have any that came from a super market or even some garden centers, check them to make sure there is only one, to maybe two bushes, in the pot. Depending on the size of the pot, repotting them may well be in order. I once found 5 mini rosebushes had been placed in the same pot and repotted them into their own pots giving me 5 nice pots of blooming rosebushes.