It's really quite simple, folks. This is not rocket science.
Nobody is talking about using checklists as a "do" lost. If you don't know your airborne checks, you shouldn't be there.
If you're really bothered about the money you're spending for 5 minutes extra on the ground getting yourself organised and the aircraft configured correctly etc. etc. then you should give up now, because you'll never be able to afford it.
No, a C152 is not a complex aircraft. So where do all these idiots think the line is for which aircraft you use a checklist for and which you don't? VP props? Retractable gear? Both? Turbochargers? Multi engine? Give me a break.
People will always be slower when learning than once they've got it sussed. Do NOT teach them cavalier attitudes. Teach them professionalism. Otherwise, once they THINK they're cool hotshot aviators, procedures will go to pot. I've seen it happen. I've had to instruct almost from scratch a guy who wanted an IMC rating. He had several hundred hours in his own Cub. Any time I told him to do a FREDA check, or to run after landing checks, his answer was "I was never taught to bother about things like that". This guy was downright dangerous. His attitude was that he knew it all, he had no need of a checklist. Actually, he knew just about nothing. He didn't even check the DG on lining up on the runway (I once saw it 40 degrees out, and let him sweat. He was really quite angry with me - "Why didn't you tell me it was that far out?"
His problem was complacency. Ensuring all checks are done is professionalism. He couldn't handle the concept.
In the air, run through all the actions. Then get the checklist out and doublecheck yourself. Multicrew you have someone else checking you, and THEN you still run the checks. Singlecrew if you miss something, how are you ever going to catch the omission without a checklist? If you think you're that clever that you never will miss anything, then let me know who you are, because I never want to fly in the back of any aircraft that you're flying.