I don't use A rated life support any more because I have a courier for combat, which has had its tiny canopy breached a grand total of 0 times. But earlier on when I had a DBS (awesome ship for the money btw) I had an A rated life support and went on a massive string of cockups that involved me trying to dock with a breached canopy, forgetting to ask permission, waiting outside the station with the timer running down again, and the security services starting on me because I had a bounty.
Yeah, that was the most tense flight out I've done so far.