We need dps and lots of it. I run back to station and switch into my Brutix that has been awaiting this day. That's when I realize I had previously stripped the Brutix down to its rigs and a DCU. Can I refit it with what's in the hangar fast enough? Pah, switch to the next best thing and undock.
Does this happen to you? My life is pretty simple - most of my assets are in one station, and that's not a FW or null-sec station that could flip, so I'm sure those people have it even more complex. So how do pilots who are more serious than me keep all this straight? Here's what I'm trying to do, but I'd love to hear what others do.
The Simple Way - Don't buy what you don't need now.
I have a friend for whom this is simple. I gather he keeps a very few ships and buys on demand in a hub when he loses a ship or wants something new. The price for this is that he's constantly losing money on the sell and buy side, plus the time needed to fit something up. But it fits his play style. He also has a high enough security status to waltz into a major hub - something I no longer have.
Rename Unfit/Partially-fit Ships to ZZ-Bottom
No, not ZZ Top. I used to rename stripped ships to "Stripped." But then they show up in the middle of my hangar list, and I lose track if they have rigs that dictate a purpose. I'm now renaming them to "zz" plus function/hull name so they drop to the bottom of the hangar list. For instance "zzBrawlRax" might be a Thorax I'd stripped to the rigs, but those rigs mean it should be rebuilt as a Brawler. Note: this never happens because I'd never strip down a brawling Thorax - I always want 'em.
Keep a shopping list outside of the client
When I start to fit a ship and realize I'm missing a fitting then I immediately add it to a shopping list in a Google Doc. This helps in case I want to ship things from my alt, especially since they can actually get into high-sec hub systems without the faction police getting all frisky. I fit the ship as far as I can from my stores so I don't run into "one more thing" later, then rename it using the "zz" nomenclature and put it aside.
Groom in-game fittings
I recently went to fit a Tristan in a hurry and grabbed a likely looking named fit from the fitting panel in Eve. Fortunately I looked at it twice because it was a two-missile / two-railgun Tristan from before the T1 frigate rebalancing pass. Other than being amusing the only reason to have that in there is to mess me up later. I've made a note for myself to go through my in game fittings and clean them up. I don't have too many in there, so it should be decently quick.
Keep Must-Have Modules in stock
There are some modules that I try to always keep in stock - preferably double digit counts. DCU IIs are an obvious one, and Light Neutron IIs used to be like that for me. I probably should move those to a Google Spreadsheet that pulls against the Eve API and link that to the shopping list.
I used to use containers. However, the fitting tool won't look into of containers, so you don't want to put anything fitting related inside of them. Plus the first time you have to move home you'll regret those Station Containers.
So, what do you do for asset management in Eve?