Have our property tax bill, and just wondering if there was any reason to pay it this year (2019) versus next? We already paid last years taxes in Jan 2019... so if we paid it this year we would have double. Just wasn't sure if anyone found a loophole or situation that made it advantageous to pay it in 2019 versus 2020?

With new SALT deduction limits, it likely doesn't matter since the deductible amount is capped at $10k (someone correct if that amount is wrong).

if it helps, the tax bill is 8600... so if there is a limit of 10k, i guess it makes sense to not double up... (will be filing joint married if that matters)

Depends what your other deductions are in a year. The standard is $24,400 for married filing jointly in 2019. So you'd need a lot of mortgage interest and charitable contributions to get above the cap on top of the property tax. If doubling up and adding the extra $1400 in one year makes a difference might save a few hundred dollars if it gets you over the standard deduction. If you are over the standard deduction by not doubling up that might make more sense.