Say that a domain has been sold in auction in the past for a decent sum of money and that domain was dropped and no one picked it up - Is it a good idea to pick up that domain thinking that it could sell for AT LEAST the price it sold at before OR do certain TLDs depreciate in value making them no longer desirable to register?
If it was auctioned on ebay for .99 then no. I'm sure that's not what you meant, so apply some DD. If you are trying to derive value solely on the price someone previously paid then it's a gamble. If the domain has other attractive attributes , bonus! Gut check it. I'm guessing that the name doesn't have intrinsic value otherwise the emphasis wouldn't rely on the past sale. I sold a .us for 2.5k+ but I wouldn't buy it back/now for $30 even considering previous sale.