I always do it on post it, much faster than phone.
I learned a relevant tactic from a ~90 year old customer: He had all his marbles but his mobility was fairly shot and he had carers coming in who did his shopping. He typed up a generic shopping list on his computer of all the things he was likely to ever want, then before they arrived he printed out a copy then ticked the items he wanted them to get on that occasion.
On my phone, I have the generic list then next to an entry I'll usually write how many I have or sometimes I'll write how many I want. When I do a stock-take, I re-write the have/need bits of information and leave the item list intact.
The other advantage is when I'm either preparing for a shopping trip (though these days we tend to do online deliveries) or I'm going to a supermarket without prior planning, the content of the generic list serves as a reminder of items I ought to consider.