MTTF / MTBF to Weibull distributions

Moving from time invariant failure patterns to time variant ones. Mean time to failure (MTTF) and Mean time between failures (MTBF) are a great entry to the world of reliability engineering, but you will soon hit their limitations. The use of a time variant function is mandatory for advanced analytics, so here is how you level up your failure rate game.
Weibull Fitting online = www.wessa.net/...
Reliawiki = reliawiki.org/...