Second Load & My New Trailer

Main thing is good fresh grease. If they haven't been greased (or inspected) in awhile, ain't no time like the present. You'll need new wheel seals, but those shouldn't be hard to find, and in a pinch, if you're careful enough with them, you could go back with the old ones if you had too, but you'll need to know what you're doing. If you're in an area with a trailer maker (or manufacturer, who even makes their own axles), you might check with them to see if new seals are readily available. Sometimes they've just got to get the ol calipers out, or a micrometer, but they should have numbers on them It wouldn't cost nothing to pop the outer covers off and look to see what the grease looks like, and to raise the wheels to check for freeplay in the bearings (there should be little to none) and check if they're turning freely with no rough spots. If you put some grease on a clean paper towel, you should be able to tell if it has accumulated many metalic particles, and if it has, be a good idea to tear em down, and clean all the old grease, possibly even replace any faulty/worn bearings, and go back with fresh grease and new seals. (if you need any help with it, i'm just a message away)
I also put marks on mine, both sides, when I have it loaded, and parked on a fairly level surface, just lay a regular level on top of the tire, and put a mark over onto the trailer. After it's been weighed, say you had 900 pounds, just put a 9 beside that mark. I first did this with a load of 40 pound bags of cement, on a little 1/2 ton pickup. It was on sale and I got a half ton, loaded it evenly into the truck, put a mark on each shock, and each 200 pounds thereafter as I unloaded it. From that time onward, I could check the marks on my shocks to see what load it had. You can do much the same with your trailer, but it takes a little bit of guesswork, as it can be heavier left to right, front to back, plus the load on the tongue, being transferred to the rear of your truck. I still prefer having a few marks to guess by, than just guessing blind