One of the areas of the AD&D 1E Vancian Magic system that I've always enjoyed is the idea of Material Spell Components. Yes, I've sat at a table and played with DM's that required a systematic approach ranging from listing every component in detail to even needing to quest for specific, and I might add, common ingredients so that the mage could ply his trade. Other DM's never worry about them, simply saying you cast the spell and here is the result. I'm guessing the majority of DM's (and players) fall in the latter category as well.
I fall somewhere in between those two extremes.
As for my current campaign, there is an Alchemist in the group whom has been collecting various items, which may or may not aid him when preparing alchemical concoctions down the road. The Alchemist to me is a class that fits tremendously well into my vision of a campaign world, and also promotes this collection process that I think all Mages should use to their advantage.
Collecting the poison from a slain spider happens regularly for the fighters and thieves in the party to coat their weapons.Yet, when the same party walks into a deserted lab and see scrolls and potions sitting with dust on a shelf, there's a mad dash to grab the first one. Left alone on that same shelf, sitting under that same layer of dust is a literal plethora of riches for the mage (and anyone else) willing to do a bit of investigation.
Case in point, last gaming session I ran, the intrepid party was in the the Dark Chateau. In the basement, behind 2 angled purple curtains were tables and alchemical supplies on raised platforms. One of the shelves had a secret catch, and when it was manipulated, a grating sound could be heard. To the players (whom had just been discovered by a hungry Hook Horror) that grating obviously was connected to the part of the wall that slowly lowered, revealing a triple set of mirrors in an alcove. What the party never investigated was the shelve on the far wall, sitting out in plain sight. On it was a veritable trove of goodies ranging from powdered diamond and a small vial with mercury, to four pea sized crystal balls and a small bag with a candle.
For the mage, these may just be spell components, but the party threw away 600 gp in materials that could have been sold back in Yggsburgh. Does it bother me they missed it? Not really, but to that end I've decided to combine all spells from the Player's Handbook and Unearthed Arcana that need a material component into a single document for easy reference.
Material Spell Components