High Press uses a lot of extra condition so use it wisely. If you're playing an easy team don't bother because the condition saved can be used in training which will increase your overall quality. I never start a game with high press because if you use it the whole game your players will tire a lot. I therefore use it like a turbo button when I need a goal or at the end of a tough match to preserve a win/draw.
For the same reason, I try to use condition bonus wherever possible (eg in easy games). Sure, you might only win 2-0 instead of 4-0 but a win's a win and I would rather save condition for training to increase my team's quality.
Thanks. I always wondered if the condition bonus saved or used condition! Very handy to know as I couldn't find it in the forum's