The terry is used for drying, removing waxes, dusting, applying interior stuff, Windows, etc.
The Suede is used for final buffing of paint and glass.
You cannot have enough MFs. once you try them you will fall in love and want more. I suggest a minumum of 5-10 to start depending on price. Buy what you can afford.
Just think how many Cotton towels you use and the sqaure footage. Then buy the same amount in MF.
Good Luck!