Dan's Maxims: Two of everything, Keep the Source, and Max out your RAM - Eventually

Always get two chargers.

It's usually easier to just accept the cost of duplication than to attempt synchronization and deduplication. The latter is really hard to get right and the costs of mistakes can be very high. The former is just a matter of storage capacity. I know which I'd rather pay the bill for.

Always keep the original source files in the highest resolution possible. You can always throw out unnecessary pixels as needed for a particular use, but you can never get them back again if you get rid of your originals. And what's unnecssary resolution/detail today will work great.

Max out your RAM - eventually. But don't do it when you buy the computer - wait a year and then buy 3rd party upgrade from a really good RAM manufacturer like Kingston or Crucial. The cost will be 25% of what it would've been to max out the RAM from the OEM. Plus you'll get a nice shiny "whole new computer" feeling just when that first blush is wearing out. (This strategy is optimized for budget-conscious geeks. Businesses and non-geeks should probably use different approaches to system capacity planning. Except businesses that are comprised of budget-conscious geeks.))