Leaking tires... tube or replace? If replace, which tire?

[GearHead36]

I have a 2016 Cub Cadet Pro Z 100S (steering wheel). It's a commercial mower with just over 400 hrs. One the tires has a slow leak. The other 3... have VERY slow leaks. The fastest leaking tire needs air about every week. The other 3... about every month.

Given that the tires are 9 yrs old, should I just go ahead and replace them? Or tube them? 3 of the 4 still have good tread. One of the fronts is more worn, and no, that's not the one with the worst leak. I'm guessing that it's been replaced. The tires don't sit in the sun now, but I suspect that they did until I bought it two years ago.

If I should replace... which tires? Go back with the original Carlisle Turf Masters? Are there any other tire that would be better?

I got a steering wheel ZTR because of the hills & slopes on my property, so I need something with good traction.

 

[Auto Doc's]

Take them to a tire shop and confirm the slow leaks, they my just need new valve stems. If tread is good, put tubes in as long as the tire is not badly dry cracked and rotted.