Just so this is not all one sided.
Adding liquid
ballast or wheel weights depends on your needs and situation,
but most folks that have loaders have liquid ballast in the rear tires.
Depending on what tractor you're looking at, wheel weights maybe another possible alternative.
(On some model tractors the manufacture does not offer wheel weights.)
Wheel weights offer the flexability of adding or removing the weight when required.
However, wheel weights can be well over a 100 pounds each, which may not make it that easy to add or remove.
A ballast box or heavy implement is another alternative.
However, a ballast box or heavy implement adds weight to the rear axle and wheel bearing assemblys that liquid ballast and wheel weights would not.
Then again, a rear ballast box or rear heavy implement helps take weight off the front axle assembly when doing loader work,
which is something that liquid wheel ballast or wheel weights would not do.
So what is often recommended, is a combination of rear liquid ballasted tires or rear wheel weights and a ballast box or heavy implement, when doing loader work.
My previous tractor was a 1969 Ford 2000 with no loader, and had calcium chloride solution as ballast in the rear tubed tires.
I was unable to finish mow large portions of my lawn/pasture during various times of the year due to the weight of this tractor on soft ground.
Also I had to have one of the rusted thru rims repaired due to the corrosive liquid ballast.
For my new Kubota B7800, I am one of the few who did not have liquid ballast added to my rear tires, and wheel weights are not offered for my tractor.
My loader manual states:
"When mounting a heavy rear implement, liquid in the tires may not be required."
I always have some heavy implement attached to my 3 point hitch (mower, snowblower, or a loaded carryall)
My loader work has include moving snow, firewood, a few rocks and cement blocks. For heavy items I pick up slow and move low and slow.
The majority of my tractor work is either finish mowing or snowblowing, with occasional firewood hauling on a 3 point carryall.
I wanted to keep my tractor as light as possible, for finish mowing work, so as not to rut soft areas of lawn with my tractor tires.
Which is the main reason I did not have liquid ballast added.
60 % of my finish mowing is on a steep hill and occasioanally I have to engage 4 wheel drive when my rear tires
do not provide enough traction (wet grass), but my tractor is still very stable without ballasted tires.
Having no liquid ballast in my rear tires has worked out really well for me in my situation, but would not work for all.
So, if you are like most folks, who do not require their tractor to be as light as possible for certain applications,
then I highly recommend a non corrosive liquid ballast or wheel weights for your rear tires.
If my situation was different, I would probably have one or the other too.