Having to replace bushings and bearings related to motorcycle suspension has been a normal maintenance routine since the beginning of time.
There seems to be a wide variety of mileages where the swing arm bearings and rubber mounts need replacing.
Keep in mind the rubber mount design also has 3 stabilizer links that connect the engine to frame and allow vertical movement from engine vibration.
They also maintain side to side alignment of the engine and frame. Make sure they are tight.
In addition, there is a pivot shaft that supports the swing arm bearings / bolts on the outside, and goes through the rear mounting lug on the tranny case.
If the pivot shaft is loose in the rear mount lug, it will need to be replaced also.
Lube and properly tightening steering head bearings are also important part of the process. ¹⁾

You can raise the bike on a jack and see engine swing better when pushed than while sitting on the tires.

One option instead of replacing the mounts is loosen all the mounts up slightly, run the motor for a moment then go back around and re-torque them. ²⁾

You can use a couple small automotive scissor jacks, one towards the front and one towards the rear, to support the weight of the motor and give some flexibility in moving it around to line things up. ³⁾

The manual says they need to be inspected every 10k, but if you're running the OEM rubbers, you can pretty much plan on replacing them at about 30k, ish. Some have replaced them after 10k. Others reported 50k to over 100k and no problems.

• OEM mounts:
  If you don't want more vibration, use the H-D mounts, but plan on replacing much more often. ⁴⁾
  They seem to be soft and to not last. There may be a lot of sportsters with softened or sagging mounts that need replacement. ⁵⁾
  • Front Motor Mount Isolator (2 each required): H-D 48463-04A
  • Rear Motor Mount Isolator (2 each required): H-D 48492-04A

• Drag Specialties mounts:
  The DS mounts seem to be slightly stiffer than the HD mounts.
  Some extra vibes have been reported using the poly mounts under 2K. ⁶⁾
  Handling is also reportedly improved over the OEM mounts.
  • Front Motor Mount Isolator (2 each required): Dennis Kirk 140553 (Drag Specialties 0933-0054)
  • Front Motor Mount Isolator Kit - includes 2 isolators & new hardware: Dennis Kirk 1400195 (Drag Specialties 0933-0117)
  • Rear Motor Mount Isolator (2 each required): Dennis Kirk 140554 (Drag Specialties 0933-0055)
  • Rear Motor Mount Isolator Kit - includes 2 isolators & new hardware: Dennis Kirk 1400196 (Drag Specialties 0933-0118)⁷⁾

• Vance & Hines mounts:
  Sold and made by Vance & Hines.
  They will require you to sign a release where you agree they are for racing only, and V&H isn't liable if bad things happen.
  From XLForum member, Nytstr: ⁸⁾
  The bike corners like it's on rails, and the wallowing, suspension taking a 'set' is totally gone. It's like a new bike entirely.
  There is increased vibration, as one would expect. But so far it is not real bad, just a buzz in the seat mainly, and certainly livable for me.
  

Note: Some advise against hard poly mounts for fear of cracked cases.
Polyurethane mounts are good but they do transfer vibration a lot more than typical rubber. If you replace one piece of rubber with polyurethane you need to do all of them. ⁹⁾
Polyurethane is stiffer, it will transfer some movement and vibration to the non-polyurethane mounts causing them to wear faster and have funky movement.
They will not reduce lateral play of the swingarm and will not improve handling because the rubber mounts do not control lateral play of the swing arm. ¹⁰⁾

OEM vs Drag Specialties. 11)	Vance & Hines version. 12)