Where do you live that means your insulin need to live in an insulated bag?my diabetes kit lives in an insulated lunch bag, so it's easy to forget.
Insulin is fine at room temperature for 30 days. The only time I have bothered with any form of insulation for my insulin is when I am spending hours outside in a very hot climate.
I prefer to keep my kit as small as possible. That means as little packaging as necessary. Meter cases and pen cases are thrown as soon as I get them. At home, I keep it all in a small bag and stock it up with needles, insulin cartridges, strips as I am getting low.
Probably, like you, I do not carry a handbag so I need to remember to transfer the bits of the kit I need for the trip out of my bag and put it in my pockets. When the missing part is insulin, I have eaten salad or something low carb.
Yes, I am human and I have forgotten in the past. I think it as much of a rite of passage as forgetting whether we have taken basal insulin.