That's some good simple rules Jeka.
I'd like to add an observation... become cautious when a hyip is in the spotlight.
This has happened many times, a hyips starts off small, pays regularly for a couple of months, then it starts appearing all over the discussion forums, that's when the trouble tends to start.
High exposure seems to lead to hacker attacks, large investments and often speculation. Any one of these seems to lead to the closure of these hyips.
I tend to switch to 100% withdraw when I start seeing a hyip all over the forums

once i get my original spend back, i might reinvest some.
cheers