I have a lab and a collie who are 10 and 12. Don't know if we've just been lucky but they've never had fleas. Always treated with frontline about every 6 months which in recent years I've bought at chemist/pet shop.
A couple of months ago they caught ear mites and my vet recommended using Advocate as this works on both fleas and ear mites. All good - worked a treat! Now I've found out that treatment is recommended monthly. I think frontline is 2 monthly but I've never done it that often.
They do mix with other dogs when out and go to kennels.
How often do you treat your dogs and how often?