Do you buy packs, singles, booster boxes, full sets, etc.?
I usually buy a single booster box of each set as it's released along with the one or two Elite Trainer Boxes that come out alongside it. Even after the massive expansion of ultra rare and secret rare cards in main expansions, I think it's still worth it to at least eliminate most of the bulk, though with the sets getting larger and larger, even that isn't fully covered by a single booster box anymore. And getting the ETBs I do because I also collect those. Sometimes it covers a good chunk of the bulk I didn't get from the booster box. And with both of them it's a real good chance I might get the chase card for the set, which is always a relief to not have to buy as a single. It's a pretty low chance, but it helps a lot when it does happen.
Do you start with current released sets or from Black Star promos in mid '90's?
I sort of jump around from set to set. I do tend to put more of a focus on the newer sets, but once in a while I get real nostalgic and buy for an older set. Right now I'm putting all my focus on Hidden Fates because I know those cards will become real valuable in the future, but following that I kinda want to go back to Gym Challenge or Dragon Frontiers. Occasionally I also just buy random one-off cards because I kinda want them. Like a random card from the HGSS days or something. Sometimes they're not even that valuable. I just like the card. Haha.
Do you look to first have a full set, then focus on getting those Mint to Gem Mint conditions? Or do you build the set one single at a time?
I rarely add a card to main collection if it doesn't meet my standards. In general this means that it has no blemishes and the centering is good. If one border is more than twice the width of its opposite border, for example, I will probably seek to replace the card, though sometimes I use the uncentered card as a placeholder which sometimes leads me to forget I wanted to replace it. In some cases, especially for really old cards, I will add a card to my collection even though it has some very minor edge wear or a really light scratch on the holo. The tolerance for those kinds of blemishes is pretty low, though.
How long do you wait to lay down more money to get singles/sets graded? Do you think grading is over rated and over priced? Or graded condition is not important?
Most of the time I don't bother with grading. There are some I might go the extra mile for because they're valuable, as I might do for shiny Charizard GX or something, but for me that means it will be an empty spot in my binder unless I plan to get a second one, and I tend to debate if I want to make that trade-off. So far I haven't had any of my cards graded.
Do you keep them in a humidity controlled room? Light controlled? Are they in plastic trading card binders or archival non-destructive protection products?
My cards are all stored in individual KMC perfect-fit card barriers and put into BCW 12-pocket binders that zip shut. It's not the greatest protection in the world, but it's good enough for me. My binders are color coded by what kind of collection goes inside. For main sets, I use alternating black and white binders. For Black Star Promos, I use green binders. For Trainer Kits, I use a red binder, and for Recurring Promo sets like POP Series and McDonald's sets, I use a blue binder. For other more obscure cards, such as unnumbered energies, winner cards, Art Academy cards, Victory Medals, etc., I plan on using a brown binder, but so far I don't think I have enough of those to justify a binder for them. I'm also debating whether or not to put the unnumbered energies in their own binder.
Within each binder I try to make it so there are no free spaces. So wherever a set ends, the very next slot will start the next set. This unfortunately does mean that a great number of sets are split between two binders, but that doesn't bother me a whole lot.
The bulk of my collection sits in these binders, which have varying degrees of fullness. I also have two ETBs full of other cards for my collection which currently don't have binders, but they will get some once the binder they would go in would be able to be filled enough.