I realize factory built wheels don't come with spoke prep on the threads. How will this affect the durability of the wheel?

What's spoke prep?

its this stuff you put on the threads of your spokes when building the wheel. It lubricates the nipples for easy turning and then it acts as a mild loctite to keep them from backing out. As for the machine made wheels, they have have to use spoke prep for their things, they should use SOME lubrication though. If they dont, thats beyond me.

Hmmm... never used it myself. Obviously the builder of the wheels that came originally on one of my bikes hadn't heard of it either. Bad wheel. In fact, most of the new bikes I've seen have wheels that don't use "spoke prep". But then I have been lucky with others. Built my own or maybe the bike shop has done its job.

Have any recommendations?

Be careful, pc2. You are new to this.

I used lineseed oil on my wheels that i have built. Very happy with it, some say it lets the nipples back out over time and you should let them set for a week, but that was fine since i had to wait for brakes anyways. ANd im not daring enough to go without brakes

Search the forum, this was argued extensively a couple weeks ago.

Yes it was indeed.