Question: Do you want to gain money while away? or do you want to beable to use your items when you get back?
If you want to gain money then sell them, but remember that you have an equal chance of losing money also.
I personally would keep everything. Whenever I buy an item I buy it to use, not to merchant. I don't care if the price dropped right after I got it or if it rose since I wasn't going to sell it anyways. My items aren't just cash value to me, they're tools. If their cash value changes, that's fine, but it doesn't affect me. I paid 3m for a whip when I got it a few years ago and the price has risen and dropped since. I never sold it because I bought it to use and I value it at 3m.
Another scenario was when I bought my SS: I bought it for 8m, it dropped to 6m pretty soon after. I was annoyed yea, but I didn't sell because I bought it to use. It hit 11m a month ago, I could've made a 37.5% profit of I had sold it, but I didn't sell it. Current price is about 10m, still doesn't affect whether I sell it or not.
Sorry if this sounds harsh, it's just the way I value my items
