Experience.
Listed martial arts are/were practiced mostly on a weekly basis. Only for judo I've trained 4 times a week during that pre-final year (in preparation for the exams).
Current
- Kickboxing: 3 months and counting, from age 33 onwards
Past:
Main
- Judo: Dan 1 (black), 13 years at age 8-21
- Wado Ryu Karate: Kyu 6 (orange), 3 years at age 24-27
Past: Side
- Tang Soo Do (including knife fights): 2 summers at age 25-26
- Tai Chi Chuan: 6 months at age 22
- Capoeira: 4 months at age 22
- BJJ: 1 summer at age 32