This thread has degraded into irrationality.
1. Camera with working light meter. OK, use it. Or use an external hand-held light meter if you want to. Done, issue closed.
2. Leica (or Rolleiflex, etc.,) with no light meter. Use an external light meter. It can be shoe-mounted if reflected metering is suitable. 10+ compact models are sold now, and they work well.
3. M6 with broken light meter. Have it fixed or use an external meter.
4. No light meter, use Sunny 16 rule. We hear this superior pandering all the time ("I don't need a meter, I can guess perfectly.") Good for you. Just go buy a light meter and use it.