Build a body-change record you can keep for three months

I want to start tracking my body changes (e.g., skin condition, physique, sleep, or exercise performance), but every time I've quit after three days. Help me design a recording method I'll actually keep up.

[What I want to track] (e.g., skin condition / weight and physique / sleep quality / running performance)
[Why I want to track it] (e.g., to confirm whether a new skincare product works / to know how staying up late affects me)
[Time I'm willing to spend daily] (be honest — usually 1-3 minutes)
[Why I quit before]

Output:
1. **Daily record items**: at most 5, each explaining how and when to measure. Conditions must be fixed (same time, place, lighting), or the data isn't comparable.
2. **Three weekly review questions**: just three, answerable in 5 minutes
3. **Three designs to lower the chance of quitting**: concrete measures targeting my stated quitting reasons (don't say useless things like "have willpower")
4. **What to look at at week 4, week 8, and week 12**: when is it meaningful to judge whether it's working?
5. **When to stop self-tracking and see a doctor**: clearly list warning signs

Note: this record is for self-observation, not medical diagnosis. If you have clear discomfort, see a doctor directly. Traditional Chinese, Taiwan usage.