Skinner, IMO not much you can do to repel ticks, they cling on me even when I use the spray. Back bay places are full of them. Right now the tick population is blooming, so check yourself every time when coming out of there.

As for the other ones, I like 100% deet, or even something as low as 21%, if you spray it all over. Come summer, there are some places and points of land where the mosquitoes and flies are unbearable. I kinda like it that way, it keeps the human traffic down.

Cover up with that stuff. Bear in mind it can ruin the fabric on some wetsuits and outdoor gear, so read the instructions first.