Right now, I am counting steps each day and I logged them on paper everyday, as close to midnight as much as possible. Only yesterday did I achieve my 10,000 steps goal. I have only been doing it since Sunday. This is my fourth day. Yesterday, I started logging my weight (on paper) to see if walking 10,000 steps will help me lose weight. Granted, it's rather manual, but also easy to do. If I try to purchase a pedometer that syncs to your computer automatically, it will costs me 99 USD brand new. Adding wireless output to my weighing scale will cost money too. There are two conditions that could lead me to purchasing sophisticated solutions: I am loaded with money and or I am overwhelmed with data input.
For now, the important thing is that I keep doing it for 30-60 days for habit formations.
What are you doing for self-quantification?
I track all of my "I should do this daily or almost daily" tasks/habits. (Review TODO lists, schedule things for tomorrow, chores)
I will also occasionally record what my "mental clarity" feels like on a scale from 1 - 5. I don't yet do this often enough for it to be worthwhile, and I may just stop altogether unless I figure out a useful system.
The best thing I have found for my personal habit formation is https://chains.cc/ but there are a lot of "riffs" on this idea out there. I have one desktop on my computer dedicated to tracking all of the things important to me (chains, calendar, TODO lists, long-term goals). I have Google Calendar "event" that creates a popup on this desktop every day at 5:00am, so that ensures it is the first thing I look at.