For me it's often in the shower after work. Which is a pain because then I've gotta remember them until I get out and then find a way to remember them until the next day.
I got a good tip for this once: throw the shampoo bottle out of the shower onto the floor. It’s ideal for remembering when you need to buy more shampoo, but if the shampoo isn’t empty, it will remind you that there’s something you need reminding of.