OP, I think what some posters are saying is that you don't need to remember or have a note of when your baby last fed, how much they took, which breast or when they produced a wet/dirty nappy.
Babies should feed when they want to for as long as they want to. Some days a baby will want to feed every 15 minutes, sometimes they will be content for hours between feeds. Both are ok. Sometimes they will feed for comfort. That's also ok.
What isn't ok is trying to coax milk into your baby because you don't think they've had as much as usual.
When breastfeeding you'll never really know how much milk your baby has taken and that's great because it really doesn't matter - some days they will drink faster or slower, sometimes your milk might be more or less concentrated.
And believe me you won't need to keep track of which side you last fed from. The one you last used will feel softer and emptier. The other one firmer and fuller. Just go with whichever feels fullest.
I actually think feeding logs can be quite damaging when formula feeding as they can encourage parents to coax babies into drinking a set amount, which can set an unhealthy precedent for overeating throughout life. Not to mention the stress this might cause to parents.
Honestly, just listen to your baby and offer them milk when they ask for it - either by crying or showing other signs (which you will soon come to recognise).
Good luck with your LO :)