I used to do this in the past, when I kept records in a small paper book.
In that, I kept my "win / loss" ratio of various games where possible, as this also learnt me which armies I struggled against, and which ones I played that focussed on my preferred manner of playing.
Now, while "my playing style" will be something for a seperate post somewhere down the line, and see how I evolved in this after the hiatus years, let`s just say I`m generally a "static defence player". Or artillery guy in other viewpoints hehehe.
But starting the new "career" in wargaming, I`m going to keep the records right here on my little corner of the internet :-)
Win / Loss Ratio's
vs Romano British: 0 W, 0 D, 1 L : 0%
vs Saxons: 1 W, 0 D, 0 L : 100%
vs Romano British: 3 W, 0 D, 1 L : 75%
Warhammer 40.000 (8th edition)
vs Death Guard: 0 W, 0 D, 1 L : 0%
vs Orks: 2 W, 0 D, 0 L : 100%
vs Iron Warriors: 1 W, 0 D, 0 L : 100%
vs Space Wolves: 1 W, 0 D, 0 L : 100%
vs Astra Militarum: 1 W, 0 D, 0 L: 100%
vs Necrons: 1 W, 0 D, 0 L: 100%