I've hand packed many bearing over the years, but the hardest part of the job for me was getting the hub nut to just the right tightness to assure longest bearing life. Even the "pros" can get it wrong, that's why I replaced all fiver axle bearings in Sep 2014 when finding two were noisy after being repacked a year previous.
I would have to think if your bearings were bad after 1 year that - a) they were of poor quality to begin (likely) and b) they were not done correctly (likely).
If we as owners are willing to take on this task ourselves, my suggestion would be to just replace the suppled bearings with a known quality bearing, eliminate the cheap import from the get go. And learn how to pack or repack correctly. Quality grease is big plus as well.
It is OK to use a wheel bearing packer like this.
http://www.amazon.com/Lisle-34550-H...24361631&sr=8-1&keywords=wheel+bearing+packer
or
http://www.amazon.com/GearWrench-27...24361631&sr=8-5&keywords=wheel+bearing+packer
As for bearings, buying American is getting difficult, but made in the US, Japan or Germany are good choices.
Done correctly I see no reason to do this on annual basis. Boat trailers yes, campers, not so much.
When most cars were rear wheel drive it was not uncommon to see front wheel bearings with well over 100k on the original installation.
Setting the bearing retaining nut torque is relatively simple and takes simple tools - and is different between cleaned / repacked bearings or new bearings installed.
After 4 years of use I was "thinking" about doing my bearings. Our trailer had MOR/ryde IS installed when new. MOR/ryde doesn't excellent work and I had confidence in the bearing installations.
When I had the "opportunity" to have MOR/ryde disassemble my IS after the last Goshen rally I had a chance to inspect the bearings.
All I could think was I was happy I had not bothered to do the bearings yet. They looked as good as they day they were first installed.
! Yep. That's how my dad taught me to pack wheel bearings. 
