Depends. If it's a one-off prototype/project/repair, I'll hand solder it. More than that, especially if it's dual sided, I typically can't be bothered and just send it off to a fab
Hand soldering methods vary depending on components. HASL finished boarts are a bit easier to work with as you can tack down parts before applying solder, unlike ENIG. For very small passives like 0402, I use 0.4mm tipped MFR-H4-TW tweezers. Leaded ICs with small pitch of 0.5mm or thereabouts I use a special concave Pace tip for drag soldering. QFNs and similar I pretin the pads then use hot air. No clean flux is always required, and often the more the better. I like
NC-559-V2-TF as long as one is careful to get the genuine article.
Technique does matter more than gear, but having quality gear helps a lot and makes the process easier and less error prone.
