If you already use and external lab for FECs:
One major advantage of learning to perform FECs is the elimination of expensive lab fees to have the some job done by someone else.
The following figures are based on prices for ONE sample from a leading UK laboratory, you can multiply this by however many animals you have/require analysing
External Lab Fee = £126.50 (worms, fluke, lungworm, coccidia, cryptosporidium & giardia)
If you worm "just in case":
Vets recommend treating for worms every 2 months. In order to treat for lungworm you will need to have an annual consultation with your vet prior to any prescriptions being given, this could cost you upwards of £30 per dog, then you will have to pay for the treatment itself, around £10 (6 x year @£10=£60).
"Just in case" cost = £90
Based on these calculations, worming two dogs, the Canine FEC Course will have paid for itself in only ONE YEAR.