In my twenties, I kept medical appointments in my head for me and both kids a year out. I never saw any point in jumping through hoops to put it in a calendar. It struck me as a pointless time waster to write things down that I was going to remember without writing it down -- and then have to also keep track of the calendar, check the calendar regularly, etc.
My messy stacks of papers made me look disorganized, but I could find anything important within ten minutes. In contrast, we routinely tore the house apart for an hour looking for something of my husband's.
He liked to organize and file and alphabetize. But the things he failed to organize often ended up in a heap on the floor. He did all that because he couldn't keep track of it mentally.
If your life works without checklists, don't worry about it. But if you find you start overlooking important details as you get older/busier/in a new and unfamiliar situation, you might revisit the idea.
Just don't rain on someone else's parade. Check lists work well for many situations and are especially valuable when lives are on the line for some reason (or similarly critical situations where mistakes often happen for various reasons).
Agreed, checklists can become a cargo cult. Also, checklists don't always need to be written down; just systematizing some mental checks can be helpful enough (e.g. "phone-keys-wallet").
I like to organise things in groups (for example, for paragliding I had 3 x 3 items, one for environment, equipment on the body, equipment "off" the body, respectively), or use mnemonics (before leaving plane: MaSeLToF (Main switch off, Sun guards set (and sun glasses removed from cockpit...), Logbook completed and hours noted, Tie down and chocks installed, Flight plan closed).
I have an extensive checklist for trips. I’ve also got a daily one, which is partially for helping me get the day started off right by checking off a bunch of easy tasks, and partially just to make sure I don’t miss something critical. Ever forget about a meeting you needed to prepare for until you got the meeting reminder? I have a daily checklist item to give my calendar a quick glance to make sure there’s nothing I need to prepare for. It only catches something maybe a few times a year, but that’s worth it for the 10 seconds it takes me every day.
Pretty much anything I have to do more than once, that involves more than a few steps, I make a checklist for. I take pictures sometimes, semi-professionally. I have a checklist for what to do before I take pictures (pack the bag, charge the batteries, clear the memory cards), and after (brighten teeth in pictures, remove lint/spots from clothes, pick photos to put in my portfolio). At work I have checklists for design tasks, some of which are things to do, some of which are things to consider (does this need a review from security? does this need additional monitoring?).
There are people that can keep all this stuff in their head. I’m not one of them and I know it. Having checklists reduces my anxiety levels by an order of magnitude.
In development, could be "pre-release/pre-push-to-production checks".
I've used them for video shoots too (e.g. pre-interview: "is camera charged? is extra battery on? are audio levels good? is frame ok? ND filter needed? took 10 second ambience audio sample? took b-roll?" etc.
We use checklists (to varying degrees of efficacy and adherence) at work. Obvious case: test procedures (for larger test cases and suites, not unit tests and automated tests). We also use them for things like peer reviews or releasing products to customers (to ensure we've asked the right questions, are releasing the correct product, have done all the things necessary to release the product, etc.).
Given that any routine could be made into a checklist, it seems likely that you have lots of everyday checklists that you do a good (or good enough?) job of keeping track of in your head.
Maybe for most things that you could use a checklist for, the effort just isn't worth it?
