In the main you can keep your insulin out of the fridge for upto a month...
Best practice is not to leve the pen in places such a direct sunlight, on window sill, or within in the car as these places tend to get really hot..
But normal ambient tempretures do little harm to your insulin in this country, and most people actually will use more than one cartidge of each type insuln per month...
I've managed camping under canvas with insulin with out the acess to even a cool box, I just kept my insulin pen with me as usual, then my spare supplies was tucked in under the trailer part of the trailer tent which kept pretty cool sealed in a waterproof container and just kept reblimishing cool water.. Now I use a frilo pouch that is activated by water, which is a brillient little item indeed, can any where in the world and will keep your insulin cool as you travel...
But generally under normal day to day situations there little need to worry about the tempreture of insulin in pens being out of the fridge I've carried my around for 20 years and never found a problem, even the day I left my insulin in the glove box of my car in the baking sun, didn't seem to damage it at all, the latter I have no desire of a repeat profermance though