Well yeah, I'm mainly thinking in terms of what I, and (most) of the people I play with find enjoyable. As players, we don't like DM pity handouts, we want to earn what we get (or fail) through our own abilities. To encourage that, you need a DM who is willing to let characters die if they get into situations that will kill them, but also, a DM who is willing to accept new characters that have a good chance of not dying in situations like those that eliminated the previous characters. One without the other, either you're a killer DM or a pushover, and either way you probably shouldn't be DMing.