I think youll probably wear out long before the gun.
I dry fire "something" every day, and usually multiple guns. I usually use snap caps as well, but more as a safety thing, than a wear thing. You cant have a live round in the chamber if you just put a snap cap in it.
As far as the trigger complaints go on the J frames, Im not seeing they are really any heavier than anything else I have. I just tried compared my 642 against three random others, a 10, 65, and 686, and really didnt see any noticeable difference in trigger weight. The thing more notiecable was the shorter grip (fore to aft) and where your trigger finger ends up. Maybe its more a perception thing due to leverage.
Personally, I dont see the need for trigger work, unless there is something mechanically wrong. Unless I happen to pick something up that has been worked on, all my guns have the factory triggers in them, and I have no troubles shooting them.
I do think that the constant dry fire does help to build and maintain the muscle tone necessary to be able to shoot DAO (and anything else too) well, and should be a regular part of your routine.