As soon as the lambs are born, you need to dip or spray their navels, usually in iodine, though I've always used the blue Terramycin foot spray. Whatever you use, this protects against joint ill.
What will you do about the boys, are you going to ring them to castrate them or leave them entire? What age do you want to keep them until before you send them to the butchers? Can you keep a number of entire males safely, ie are your fences/walls good?
I don't eartag until they leae my holding (or you're supposed to do them before 9 months old I think).
Personally the one routine time I worm is when I turn out the ewes with lambs, as whilst the ewes may well have built up resistance, the lambs won't have. Hopefully your rotation will have reduced the worm burden, but then I don't want ewes depositing any while they're sharing the pasture with vulnerable lambs. Others may tell you to get an egg count done on your ewes........