Ordered my first bulk order of SMD parts from DigiKey last night. 0805 1/8W resistors are 10 cents a piece in single unit quantities (plus, like, $3 shipping), but a reel of 5000 of them is only $15. And for me, that's easily a lifetime supply.
I waited until now because I wanted to get some experience with the reflow oven before committing to it as the path forward.
I can now say with some certainty that the 1.6 version of the Hydra will be the last through-hole design. Same with the current version of the EV Sim 2.
So what do you buy when starting out?
Well, first and foremost, 0.1 uF 50V 0805 ceramic capacitors. Every chip needs at least one mounted nearby across its power supply pins. Next, 330 ohm resistors. They're series resistors for NPN transistors and LEDs. 10K resistors for the pull-up on !RESET for every AVR controller.
I also got some parts to flesh out the reflow oven controller - I suspect I may sell a few of those. For them, I need the rest of the passive parts for the AD8495 thermocouple amp - 1M, 0.01uF. Also, 0.33 uF for the regulator. I also got a tape of regulators, input protection diodes and Tiny85s.
My big problem right now is firmware. I've got a number of ideas for the Tiny85, but they all involve driving a 2 line LCD display over i2c. TinyWireM, LiquidTWI2 and the Arduino core by themselves seem to take up most of the available flash! I can't hardly believe that's true. I've got to look into it to see where all the space is going.