Yeah, there are several people dropping by my shop every day asking for various specialty items. I've had several requests for Miasma slayers, for instance. And PvP weapons. A player might want one HLD/Lightning/SL/SSI/DI, another that's HLA/HCI/Lightning/SSI/DI, a third that's HLD/DCI/Lightning/SSI/DI, and a fourth that's HLA/HLD/Lightning/SSI/DI, a fifth that's HCI/DCI/Lightning/SSI/DI, a sixth that's SL/LL/ML/SSI/DI, and a full set of super slayers. And of course every warrior wants a 15 HCI/15 DCI/8 LMC/(either 8 STR, 8 DEX, 25 potions or 25 DI) ring and bracelet, and every mage wants a 3 FCR/1 FC/12 SDI/(either 20 LRC or 8 LMC) set.
Just think about it. That's a total of about 15 to 25 items per character, 5 to 7 characters per account. Over 100 items at 5 imbues per item per player who doesn't have imbuing himself. You need 20 relic fragments and 40 various essences to make just one weapon, and 5 relic fragments, 20 seeds of renewal and 30 essences per piece of armor. Then there's the shield; FC1 and 15 DCI are expensive. The reflect is cheap, but it takes 10 relic fragments, 10 essence of achievement and 10 essence of singularity for FC and DCI, all of which are expensive. It takes a lot of time and effort to collect all those materials. You can figure on like 5 to 10 million just in ingredients per piece of equipment that you imbue. It takes 20 seeds of renewal for stamina regen 3 and hit point regen 2, 5 relic fragments and 10 essence of order for the LMC, and a few hundred valorite ingots making blanks to get the right beginning resists per piece of valorite plate armor, so that you just have to use one imbue to resists per piece to get to all 70s. With seeds bringing ungodly amounts of gold, a 6-piece set of imbued valorite plate will cost like 60 million gold just for the materials.
The point is that only the players with like a billion gold in the bank can afford to pay like 10 million each for the hundred or so items that they want imbued. The rest of us will take years getting everything upgraded for all of our characters. And by that time, it'll already be wearing out, so we'll have to choose between buying another piece or replacing one whose durability is so low that it has to be repaired three times a day. There is going to be a market for imbued equipment for a long time to come. About the time the weekend gamers get up enough money to have you make them some really uber equipment, the first set of customers you made sets for will be ready for replacements.
When it costs about 60 million gold in ingredients alone for just one really nice set of imbued armor, decreasing durability to 50 would make imbuing totally useless. Nobody is going to spend 10 million gold for something that is going to be worn out in a week. And nobody is going to unravel all their artifacts and high-end equipment to make the relic fragments required to make that piece of imbued equipment, or go hunting all day in Abyss for 10 seeds of renewal or abyss cloth if the prices of the ingredients don't remain pretty high.
At 255 durability, I have to go home and repair my equipment after just a few battles with Lurg. And the grizzled things in the Abyss do massive damage to your equipment, too. Very few of us want to have to repair our stuff like 10 times a day, and have it wear out in less than a week. Let's face it, most of us are going to junk our imbued armor and weapons when their durability gets down to about 50; we just don't like to have to run home and repair our stuff every few minutes. Also, as much trouble as it is to get to the middle of the Abyss, I would hate to have to just get there, drop 1 grizzled then have to recall home and repair my stuff. For an active player, it an imbued weapon or shield will last about 200 repairs before its durability hits 60 or so and he junks it. That's a little over 6 months. A suit of armor will last about a year. That's not that long, really. I don't want the stuff to last forever, but making them useless junk isn't the solution, either. I think the durability is about right, as-is. Players will buy my items, then they'll come back for more in a reasonable amount of time.
Don't think of it like you're running a grocery store and want the same customers to come back every day; think of it like you're running a hardware store; you'll have regular customers, who will want various items from time to time. Some of them will wear out fast, others will last for years. But if you sell a good product for a fair price, you'll stay in business for many years. People will send their friends over. Other people will come by every few weeks or months. And a few will be back every week or so.