Rags, if you can identify the stuff you're storing that you use the least, that is certainly the least painful place to start. Once you get going you may well find you inspire yourself and can move into the next least-emotional space.
My eBay listings typically go up for a week. Sometimes as an auction, sometimes I add a "buy it now" price (this has to be about 33% higher now, so sometimes that price looks ridiculous so I don't bother). Other items are listed for a set sale price, no bidding, you can click on it and buy it. They run for a week and I relist, and if I decide it is too high priced or needs some tweaking, I do that before relisting. I have usually sold most things within a week, but now that I'm listing some more commonplace items they sometimes run for several weeks.
This morning I've been going through seeds packets. It's time to plant for fall (after I weed for fall) and I am tossing some of the truly ancient packs of commonplace seeds. I have a drawer-size plastic sock bin thing that I sort the seed packs by year and type (flowers or food). It goes back a few years, and what I end up doing is combining some of the older seeds in with a new batch - they get used and may grow, but I'm not relying on a several-year-old pack for the sole seed source. That said, I also think mixing years of seeds gives a little more diversity to the seed source which is probably a good thing.
It's supposed to be hotter today, but I'm tired of waiting for it to cool off so I'll be out there working for a little while. I need to weed some of the new beds and finish the front yard mowing. I watered the sweet potatoes yesterday so now I can pull the hose off of the turf and run the mower through there. (The sweet potatoes came back this year as volunteers on the berm in the front yard. I didn't have a great crop last year, but they looked so nice, so I let them stay and am watering again this year.)