A couple of posts ago I said it took 400 cave snakes to level. At level 49 I noticed it takes about 8 cave snakes to get 1% of experience, meaning it takes approximately 800 cave snakes to go from the beginning of the level to level 50. I should mention that at this stage you might have more success as an archer targeting skeletons in a group or working over green slimes (which brings both gold bags and better experience).
So why cave snakes? It's partly about the grind, and partly about daily quests. As a warrior cave snakes are no trouble, you barely even get a scratch. Archers have to run around and constantly get killed by skeletons even when they're careful at lower levels (of course a warrior would fare even worse at this stage). As you're killing cave snakes you're also picking up cave snake tongues and cave snake lamps both of which are quite useful. The cave snake tongues are one component of one of Auldsbel's quests. The cave snake lamps are used in the Doug's cave snake lamps daily quest. So why does this matter? Well at lower levels 40-50 the daily quest can really help you level. Say you have 20 cave snake lamps, each 5 give you 5000 experience and 5000 gold. This means each day you're getting 20000 experience and 20000 gold pieces.
To get 20 cave snake lamps it takes approximately 150 kills. The lower level character I tried this with took 143 while Tarq did it in about 170 (though much faster). You could store up cave snake lamps with a higher level character, but why bother, use them for bones (skeletons), and coal (mogguns).
Over the years I keep going back to cave snakes for leveling in this 40-50 range, they just seem really beneficial in the end.