I play 5 point matches.

Match 1
I am leading 3-2, opponent makes a premature double (he has an edge but it is small). He is doubling me into game. I take this 99.99% of the time, yes?

Match 2
Opponent is leading 0-2 and makes a premature double (he had an edge but it is small). I take but if he wins he is 0-4 and if I win I am 2-2. It seems to me I should redouble and I do. Mistake or not?

In situation 1 this is almost always a drop from what I know about match cubes. Match equity table assumes both players are of equal strength and if he's got anything over 50% of game winning chances (even 50.01%) it is correct to drop, at which point it will be 3-3 and you both will have 50% MWC.

In situation 2 I don't think this is an instant redouble. I believe it depends on the position but I'm not as sure as I am in situation 1.

of course, as I mentioned before, a standard match equity table assumes players are of same strength but if you know the opponent and he consistently misplays certain positions then who knows...

If your opponents double is premature then you should always take!

If the score was 4-3 then you would be right, because you would be risking 50% mwc to gain 50% mwc and 50/(50+50)=50%.

Here you are only risking being down 4-3cr (mwc 32%) so 18/(18+50)~26% (of course gammons will push the take point upwards)

It depends, but quite possibly. You shouldn't just auro-recube any position for sure. You can still win about 16% of the time trailing 0-4. No reason to throw that away needlessly. You should be recubing quite agressively of course and sometimes even as an underdog.

+1