> But also all the small parts start to add up: cables, connectors, batteries, power distributors, ...

This sure is the truth... I am painfully familiar with realizing I've spent another grand at McMaster-Carr by the end of the month with a series of small purchases, each under 50 bucks individually.

The big ticket items tend to be expensive, but expensive once. It's all the nickel and dime purchases in between that can really hurt.