Welcome to the forum.
Do you already have a WDH (weight distributing hitch)? With some types of WDH, the weight bars also provide anti-sway. With other hitches, an anti-sway device needs to be added.
Most folks on this site replace their trailer tires after 4-5 years regardless of their tread and mileage. You can check the tire date code to find how old they are.
Sherm & Terry w/rescue Eydie (min Schnauzer) & Charley (std Poodle)
2015 Jay Flight 27RLS, GY Endurance (E), Days: 102 '15, 90 '16, 80 '17, 161 '18
2006 Ford F350 PSD, 4WD, CC, LB, SRW, Cmpr. pkg, Equal-i-zer 4-p, ContiTrac TR
Full timing: Some will think you're crazy, some will be envious, just enjoy the freedom!