I always do a worm count before I worm, and then use wormer as advised by my vet. Mine seem to be resistant to panacur (white wormers), so i am on yellow ones atm. If you do a worm count 10 days after first wormer has been given you will find out about resistance.
Fluke can be included in the initial worm count, mine don't have it.
I use Fasinex on my sheep, who get fluke but no worm burden that needs treating.