Well, I have two processes going forward in my immersion with desktop-building.
Ongoing, I always need small parts of this and that -- cables, plugs, HDDs, fans.
Seasonally, annually and over a longer span, I may plan computer-building projects, each over a year's time, but there's no certainty that I will actually build them. So there's an annual budget for "household computer upgrades," and a schedule, if only a vague one. The small-change stuff is also part of that budget-plan, but the financing of it is monthly cash, if only to zero out credit cards.
For the projects (there was my X79 IB-E plan -- didn't build it; my Haswell-E project -- didn't build that either) -- I may use an account for which there's no interest charges if paid within a year for $500 or more. But I still need to find bargains. I may figure on a base initial outlay of about $1,600.
So I start reading reviews and looking at forum exchanges. I choose a processor and chipset. I start looking at motherboards, and give a heads-up to alternatives touted by the reviews, but lean toward ASUS. I'll window-shop top-tier boards, just to get a feel for the "possible." Then I'll pick a board that has performance close to the top tier, without features I wouldn't want anyway. But I'm likely to pay between $170 and $250, well below top-tier prices.
RAM reviews always give new insights, but I've stuck mostly with G.SKILL. Instead, I'm keen for searching through the G.SKILL models for the right timings, voltage, speed, and inclusion in a "configurator" link of either the motherboard or RAM maker. The QVL lists can be good for extrapolating compatibility to the same module design at a higher speed standard.
So I'll come up with a list of parts entered in an Excel spread, with columns for several resellers in my table of resellers. Shipping, taxes, delay, certainly trust and reliability figure into my decisions.
Then I click all the checkout buttons, hopefully one big one that doesn't cost me anything in finance charges. And I may wait over a two-week period, checking the tracking pages for UPS, FedEx, DHL or whomever. I have to be sure and leave the gate unlocked for deliveries, check the mailbox and so on.
I come to see it this way, though. I see it as something like surfing. You have to wait for the right wave. And when you put it all together, it should have an overall strategy that integrates case-design considerations, cooling expectations and challenges, location of storage, ventilation -- all of it.
Even if you follow some master plan you dreamed up over months, it's going to change in the process of putting it together.