Ah, the topic of spell components. Often a source of humor (swallowing a live goldfish?) and sometimes meant to provide balance (and to vacuum out every copper the mage has, How much diamond dust does a mage need? All of it!) they are sometimes given a miss.
When I first began to DM I made spell components mandatory - they casters of all stripes absolutely, positively had to have the listed components in order to cast spells. The end. You don't have a live spider? You can't cast Spider Climb. This often led to drama and drove character actions - PC's mentioning that they carry small vials with corks that have tiny holes and that they catch little garden spiders while scouting, for example. In one memorable adventure one of the party's magic-users was frantically crushing some diamonds just found in a treasure chest hoping it was enough for him to cast a Stone Skin spell that might get him out alive.
But in some games (one shots, short arcs, etc.) it was frankly too much trouble. Unless the component cost more than about 50 g.p. we just gave it a handwave. And I know I am not alone - most games that I have played in just ignore components.
In my new-ish 2e S&P campaign when I was using spell points I had a simple rule - 50 g.p. per level of the caster per adventure to cover the cost of components. So the 7th level Fire Elementalist would make off 350 g.p. just before the adventure and we assumed this covered the cost of any components he might need. Simple, didn't require a lot of paperwork, and still removes cash from pouches. I can't remember where, but I once saw material components as 'being prepared taxes' and I think that is actually appropriate. I am also careful to track arrows, sling bullets, etc. and have general maintenance charges for all characters, too.
But Seaward, my 1e campaign, still requires careful track of components.
Each city and large town has one or more magic shops (these sell components, parchment, ink, etc., never magic items) and magic shops exist in a few smaller towns. In some villages and even a few remote areas there are hedge wizards (an NPC-only spellcasting class) that either actively collect and sell components or can be convinced to sell. When a spellcaster is not collecting components by gathering them directly they usually go to one of these sources. When they do I have a chart I refer to to determine if they have the component and how much it costs.
It sounds like a lot of work, but the chart was a one-time thing and the depth it adds is a lot of fun.
How do you deal with them?