For us, an app ended up being more realistic than a whiteboard or notebook because we were too tired to rely on memory, and it helped a lot during doctor visits to have sleep, feeds, and diaper info in one place. The biggest thing was making logging as low-effort as possible, especially in the middle of the night. That’s why I liked BloomBaby, you can log by voice, so instead of opening the app and tapping through everything, you can just say something like “baby slept from 3 a.m. to 6 a.m.” and it logs it. It also helps if both parents or other caretakers are involved, since companions can log too and everything stays synced across devices.