First, you need a cleric who has the power to cast the spell. That itself isn't common -- raise dead is a complicated spell that only works for two weeks or so after death. Longer than that, and you need a resurrection spell, which very, very few clerics can cast. If you don't have enough of the body, you need resurrection too. If you don't have any remains, no raising at all, period. Then there's the cost -- five or ten thousand gold pieces depending on the level of the spell. Long story short, that level of magic is only available to adventurers or the very wealthy and important.

And trust me, you don't want to rely on the spells. I learned that the hard way. I was in a party with a cleric who could raise me, and through bad luck and tragedy, it took six months for them to raise me.