I personally don't believe in skimping on motorcycle tires. There is only one front and one back. If either goes South, the ride can be a hand full. So inspect the tires frequently looking for any sort of problem that can ruin your day (like nails or screws, worn areas on the tire, cracks in the water grooves, cracks in the sidewalls, etc.). Make sure you keep the tires aired up as indicated by the tire manufacturer, not Harley. The specs in the Owner's Manual are for the OEM tires, and if you have replaced those with a different make, or even different model tire from the original equipment model, go by what the manufacturer recommends for that tire on your bike. Call the manufacturer's tech support for a recommendation in writing if you can't find it on their webpage. Remember to inflate to recommendation when carrying more load than just the rider.
The tires on baggers generally wear out more in the middle of the tread just because these bikes typically get more straight road riding. So make sure you inspect across the whole tread of both tires. Either roll the bike around so you have seen all the tread of both tires, or put the bike on a lift so you can rotate the tires all the way round to completely inspect the tread.
Cheers,
TQ