At release of 1.x we had to had leather patches and other mats to repair, later on we got the now known dark matter. The NPC's to that time repaired max 99% for an outragous price. This has to be known first.
Atm SE has lowered the repair and dark matter costs significantly just after release of ARR because the hasting majority wasn't able to earn money and the haven't been willing to earn money, dungeons mostly have been the top priority. But shortly after the rush they realized that FFXIV ARR isn't exactly the game they played before, be it WoW or LotrO or GW ...
Back in Beta we have been able to gather dark matter, so any repair would only had one cost... time.