Re: How many times have you been saved by proper preperation on the water?
For me, in old boats, shared boats, salt water and sand, winter conditions, isolated locations, big tides, unmarked waters in the dark--I don't care how hard you work to keep things running well: these conditions are out to get you, and you have to be able to deal with them yourself. I learn as much as I can about both the boat and the environment, and try to know what signals an approaching problem.
When you ask about preparation, your boat mechanics is only half of it; you have to know about your boating conditions. For example, a lot of people don't know that your anchor is your most important safety equipment, and why. That's the sort of preparation that is as important, if not more, than knowing how to bypass a fuel or electrical problem. In some of my places, a shove pole is essential; in others, useless. No one here can tell you everything you need; your local boaters can.
Also, "preparation" is more than having a bilge pump to rely on; it's having an extra pump, a hand pump, a plug, a bailer and a means to signal distress/call for help. In other words you must learn not to rely on your systems no matter how well you maintain them. You must have back-up and/or redundancy for the important items.
I have probably rescued more people than have rescued me, and I've rescued my self a whole lot. Last year I got an 80 year old man and his son off a mud flat in a blizzard where I was the only boat out within 10 miles. Had to leave the boat. I've paddled, shoved and walked my boats out of jams plenty. To me it's just part of boating, at least my life style.
My closest call was probably when I rolled a canoe in rapids goose hunting in January; it was about 25 degrees out and we were about 6 miles upriver from our landing. My preparation, of both how I dressed and how my partner and I knew how to get back afloat, saved my life. Matches in a baggie in my shirt pocket, thermos of hot liquid, dry bag of dry clothes, helped. Two other duck hunters in a canoe died that same day.
In nature, there are no rewards or punishments; only consequences.