Regarding betas, rcs and dev, it depends on the popularity and niche your module fills imo.
If earl rolled out an official version of views that had a data loss issue the internet as a whole might cease to function.
However, if you have a small module that is relatively unpopular (>1,000 users) and youre just just going through routine bugfixes it is more reasonable to just make new releases and not beta/rc them.
if you know youve made some big chnages or seen alot of churn then test more thouroughly.
I tend to test and roll betas/rc when i am altering the DB or issuing update() hooks because i realize the permanence of data loss. I can reroll and rerelease a small bug fix fast right the world but i can recreate your sites data.
Hope that helps.