I use a software product for my Windows PC. It cost me (one time buy, years ago but free annual updates) 35$ (USD) (about 25 GBP).
It tracks all repairs, preventive maintenance checks and services due (by both calendar date and mileage), logs all trips (to calculate MPG and current odometer), tracks materiel (keeps track of sources as well) and / or labor expenditures, and allows me to attach files to each entry, e.g. photos or lists of viable filters, how to do certain tasks, etc.
Yes, I do have to put the data in.
I have 5 Morgans, each with a different engine, fuel management system, etc., and each has its own maintenance requirements.
I looked, my earliest entry is 1994. Honestly, I wouldn't know what to do (or when) without it.
Vehicle Manager 2019 - Home Edition, Version: 3.0.1008, Kaizen Software Solutions
Cheers,
Mark