Firstly, I am not a cheese maker but have at times past assisted two people. I would think the rennet will still work if it has been stored properly but with anything like cheese it all depends. One of the reasons cheeses are so varied because there are so many variables in milk, pastures, animals, seasons etc that you will just have to play round and invent something that works for you. I live at the tropical top of Oz so whatever might work here probably wont work there or vice versa.
My greek friends, in Greece, butcher a calf annually and just dry the rennet, the old lady makes a soft goat cheese on a daily basis from air-dried rennet.
I would certainly start low-tech and kick-off with yoghurts and ricotta cottage cheese styles and work your 'whey', [eek dreadful pun ] up to the masterpiece type hard cheeses.
I would love to mess around making cheese but without using massive amounts of refrigeration my climate here is too tropical to do that. Anyone know of any tropical cheese makers?
mike, Katherine NT in the hot dry tropical savannah bit of Australia.