I'd get up at half six every morning before school and note all the species that visited the garden, using an extremely sophisticated picture key to indicate where I saw them. Every so often I'd come across something really exciting that I'd never see before - like the above Willow Warbler & Meadow Pipit spotted whilst visiting family in Yorkshire - and they'd get a special 'F' written next to them (the term 'lifer' was still unbeknown to me at this point), as well as a glued-in picture nicked from Google images!
For me, as with pan-species listing, the act of keeping a casual field notebook unintentionally became a chore over time. The very point of a 'field' notebook is that you use it in the field, get it dirty and don't worry about how it looks, yet I'd find myself thinking way too deeply into how I structured it and would become dissatisfied with how the pages looked compared to other birders' notebooks. I'd typically get a quarter of the way through a notebook and then abandon it when a backlog started to form. Blogger and Twitter became an easy way to record a day's worth of wildlife.
For someone who likes to get a bit nostalgic every now and again, notebooks are a great way to re-surface past events. You can flick through months and years worth of sightings and field trips without the need to load up an app. It's just a shame I never got the hang of writing one!