Originally Posted by
ThermionicScott
I enjoy building bikes from parts, but it's not the most economical way to do it. Even if you think you're getting a good deal, you have to factor in shipping and the time spent hunting them down. Far cheaper to buy a complete bike.
It depends on what you're building, what you're starting from, and how you feel about used parts.
If you don't mind an off-brand crankset and maybe brakes, you can get a complete brand new bike for about what you'd spend on a Shimano group imported from the UK.
OTOH, if you want a bike with this year's $1100 Chorus gruppo that'll probably be a $4000 bike and you could spend less on a custom build that's exactly what you want.
Bike parts breed. Although I practice serial monogamy with my bicycles I'd just need handle bars, stem, and headset to turn a frameset into a bike.
In other situations you want something different or more contemporary and not a +1. Starting from mostly there is a lot less expensive - I joined the 10 cog era with NOS 2010 Campagnolo Centaur Carbon Ultrashift levers, used 2004-2006 Record Titanium derailleurs, and new chain + NOS cogs for $600 which would not have happened used in the form of a complete bike.
Used the way you want often isn't a viable option. In a few years of looking I've yet to see a titanium Litespeed cyclocross bike in my size setup the way I'd want or even just a frame.