You need at least 25-30% DEET to really repel the mosquitoes. In northern Ontario we also have to deal with black-flies in the spring which can be so thick they drive moose insane and they will charge out on to roads to escape. They also can make a moose anemic due to blood loss!
In the military we had 99% DEET which worked fantastic but would melt plastic and rubber including your weapon system. It disappeared when links to cancer were published. DEET works. So do thermacells, though I sometimes questions what the smoke I'm breathing is doing to me I can remain motionless while turkey hunting in the worst of black-fly season.
On your side of the border you have Muskol... it used to be 100 percent but I'm not sure now.
Muskol Insect Repellent Mosquito Repellant
Over here we have Ben's 100
bens100.com
It's 98.11% Deet and yes, it will dissolve plastic and take paint off your pencil, back when we used paper tally sheets. On the other hand so will avon skin so soft, which was a big item for bugs some years ago.
It supposedly will last up to 8 hours; but if you are active and sweating a lot it will run off.
(especially off your forehead & into your eyes... a sensation I'm way too familiar with.

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I use it sparingly, spraying it onto my hands and then rubbing it on bare skin. A little 1,25oz spray bottle will normally last me 3 years, and I'm out in the bugs all day 7 days a week.
They're brutal this year though, so I'm using a lot more.
If you're talking about applying over clothing, permethrin will be much more effective. You just need to treat the clothing ahead of time, to let the permethrin dry. It will last a long time, even through washes. You can also use it to treat tents, backpacks, and other gear. It works very well.
SD Health Dept - Permethrin facts
Permithrin is a plant based insecticide, not a repellant; I have seed which I'm going to try to grow this summer. However the bottle I'm looking at right now, which I bought to use on my dog says "Not for human use."
Also, it is harmful to fish; so I'm careful about when I use it on my dog. If he is apt to go swimming soon, he just have to suffer like I do.