In D&D 3.5, provided the spell is cast promptly and the character wasn't turned into an undead, there is no risk that a Raise Dead won't bring your character back.
I said nothing about reliability, just expense and availability.
As per the wealth by level guidelines, a 5th level character can afford a raise dead spell; in a couple levels, it won't even be a big deal. (The cost table does say that whether you can get the spell cast is DM's permission.)
Just because a thing is affordable in the books does not make it available or affordable in-game. Availability of a spell is like anything else in the game- succeptible to scarcity. Jut as the local smith may not know how to make an Urgosh (or may be backed up with other orders or may just not like your kind), the local priest may not be of sufficient level to cast RD, may not have the spell components to cast it, or may not be inclined to cast it for those outside his faith.
Or, just as likely, RD can't be used because your PC died too long ago, or had the misfortune of expiring while broke.
As for PCs, not every party has that powerful a Cleric. Our 13th level 3.5Ed group, for instance, only has one because I retired
myPC when the only guys playing divine casters of any note- neither of whom played a cleric- moved away from town. And my guy can only do so recently since he is multiclassed (a Geomancer).
At 9th level, a PC cleric can just cast raise dead. That is, at 9th level it is both cheap and common as per RAW, and starting from about 5th level it's affordable as per RAW and availability is unspecified in RAW.
See example above.
But it's not like playing poker with cash. Cash has established value; if you lose a PC every couple sessions, you stop getting attached to PCs.
The analogy was imperfect, to be sure, but analogies never are.
The point stands: if you are playing a game in which you risk something you care about, you will play differently when that risk is removed. In poker, that is cash; in gaming, a beloved PC.
FWIW, two can play rhetorical games like that: y'know, in 35 years of gaming, I've never seen a campaign in which someone lost a PC every couple of sessions. But there is an analogous situation in poker as well- if you are a wealthy individual, playing in a low pot limit or low buy-in game will mean nothing to you. If you might don't really care about the cash until buy-ins reach $10k or more, the risks associated with playing in a $10 buy-in game will be meaningless to you.
I disagree; once I've rolled up Terrance Terrato to replace Susan Sanada, the fact that Susan may have screwed up and doomed a village no longer has a bite. I no longer have to roleplay out her guilt, be her dealing with the consequences of her failure. That was a different character, that was someone else.
It depends on how
YOU felt about Susan, and what her failure means in the context of the campaign world.
As a counterpoint, I can retell the story of Bear:
One of my most memorable PCs of all time was a 1ED Fighter named Bear. I made a deal with my DM- give me maxed out physical stats and all of his mental stats would be 6-7s. Bear was a gentle giant, he fought because he was trained to do so by those around him (what else was he going to do?). Despite his nature, though, he had hooked up with a manipulative thief who treated him well...in order to have the most loyal and dangerous bodyguard he could find. That thief was- to Bear- brother, father and God all rolled up into a diminutive package that was his only true friend.
The thief eventually took something he really shouldn't have, and the City Watch boiled out of their barracks like fire ants from a kicked-over mound. As the party fled, the thief told Bear to protect him...
As they crossed a river on a narrow bridge, Bear turned and faced the entire Watch himself, taking down one after another until he died. By then, the party was safely away.
That happened 33 years ago. It was an important campaign event, and it was personally important to me- one of my best moments as a role-player. (i know those events were discussed in group for a few years, but then I moved away...)
Conversely, 18 years ago, I had another PC who died simply because of a series of improbably bad die rolls- bad enough that the mathematician in the group equated the probability to be on par with winning the lottery. Again, that PCs death affected me personally, since those events became part of the litany of in-jokes my group has: he's not recalled for his deeds, he is recalled for how he died.
If Terrence Terrato's death has no effect on you, it is solely because you were not attached to Terrence Terrato.