You are spot on man! For trailers that get dunked in water every season, you need to do a full bearing pack. If you can't do it, pay someone. We charge 65 bucks plus the cost of the seals at my shop, but it is really an easy thing to do. I helped a friend last night pack and replace some bearings on an old boat trailer he just purchased. It is a really good skill to learn, because you will be able to get yourself off the side of the road if you have a bearing fail.How else would you jack it up? Also, not sure if I'm telling you something you already know, but putting grease into zerks is not greasing the bearings if it's something like bearing buddies. You need to actually pull the inner and outer bearings periodically and grease them by hand otherwise you'll end up stranded on the side of the road.
I worked in a shop for a few years and I can't tell you how many people towed their busted down trailers in because they relied on bearing buddies.