Started this thread a while ago
I just bought my 5th pair of raws ($20 501s), and I'm happy to have spent the money on the raws I own. I didn't read much of this thread because it seemed like it was just people arguing, so I'll just throw in my two cents on the whole thing:
start cheap! there's no need to jump into the deep end right away. 501 STFs, unbranded, and naked and famous are all fabulous places to start, and won't break the bank (501 STF you can find for MAX $45, unbrandeds are about $80-$100, and N&F run about $150 from what I've seen).
Make sure you know if the denim is sanforized/unsanforized. Sanforized denim means most of the shrinkage has been taken out of the denim before being put on the shelf, so you don't need to size up to account for shrinkage. If you get unsanforized (501 STF is a perfect example) I would size up 1 size on the waist, and maybe 2 inches on the inseam (for a "normal" fit, if you want baggier or skinnier you can upsize/downsize accordingly). Sanforized denim I usually size down one or 2 waist sizes for a slimmer fit but again that's preference.
It's not a bad idea to soak, regardless if they're sanforized or not. If they're unsanforized, you HAVE TO soak. If you don't they'll shrink A LOT on the first wash, and all of the fading you've started will shift and look strange. Soaking sanforized denim isn't necessary, but I do it anyways just because it doesn't hurt anything. By soaking I also mean sitting in the tub with the jeans on. The hotter the water, the more they'll shrink. Chill in the tub for like half an hour and you're good to go! Wear 'em till they're dry or hang 'em up, it does't matter too much.
Denim stretches, whether it's sanforized or not. my rule is that if I can get the waist all the way buttoned up at all (even if it's batshit tight), then it'll stretch out enough. I even did this for my 501s before I soaked them, and the waist still stretched enough afterwards that they're comfortable to wear and not too tight.
Go as long as you can without washing them, but there's no need to be extreme. If you spill a ton of shit on them or they smell like moldy assholes, throw them in the wash! They're jeans, not silk dress shirts - they'll be fine. If you do throw them in the wash, you can minimize shrinkage/fading by turning them inside out, washing them by themselves, with cold water on a gentle cycle. Hang dry (dryers are not good for denim), and then wear when they're all dry. If they just smell but aren't stained, you can also just soak them in the bathtub and swirl some detergent around, which usually does the trick for me.
That's all I can think of right now, if you have any other questions feel free to PM me!