A very simple trick I have been doing for years now. When my bikes are new from the start cheap or higher end I drill about a 1/8th inch hole through the center of my hubs. This makes just like a grease cert. Sometimes I trick them out with a official grease cert threaded in sometimes I just leave the hole . With just the hole I have to butt up a rubber gasket between the grease gun and the hub of sorts. A couple of good pumps and the hub ends will squirt out old grease done deal.
I hate sitting there feeling picky about the preset end play with cone wrenches. While its not that hard to do I figure why make my life any harder! This way I set the end play up right and leave it. On some of the cheaper lower end rear hubs it would have a weak all thread axle there I would up grade that. Among my favorite slightly higher end hubs skewers type. I loved those hubs. No warping Axle ever I set the preload right those hubs ran forever with a grease gun !!
I figured over the years on a rear hub preload set right with my grease gun I never need to fondle and stare at the bearings that set up could easily go 6000 or more miles. It always out lasted my spokes! ''Lower end set ups''.
Front wheels always last forever..