Little late to the party, but we stopped using flea/tick meds several years ago when we realized our Lab was allergic to Frontline.
She developed a dry skin/dandruff condition when she was six months old. We tried everything including vet visits and all the expensive dog food brands to clear it up, but nothing worked. We finally realized it was the Frontline when we switched to another brand of flea/tick control and it cleared up immediately. We decided to try not using any meds after that batch was used up and we've found maybe 1-2 ticks on the dogs since then... honestly, about the same amount we found on them when we were using the Frontline. Our dogs are either inside or on our deck, so YMMV.