I'm a novice sewer...and I have been asked to put tabs on curtains using very good quality microsuede; and asked to lengthen the curtains...do you have to "hem" microsued or are the edges stable enough on their own?

Microsuede tends to curl up, I would suggest a 1"hem at least. Are they lined? If so, use a blind stitch possibly for a more finished look.
Also use pinking shears (if you have a pair) it might help a little on the curling aspect.

Thanks for the info as "I have NO CLUE". Almost afraid to cut the material for fear I make a mistake "with their $money$". But, I warned them so...it's off to the machine.

Let us know how they turned out.