As has been mentioned...nitrogen does not provide any significant benefit than filling your tires with regular air (again about 75 - 80% nitrogen...your in Florida I see...you will not notice the difference compared to someone who puts nitrogen in a northern climate in the winter). Frankly I don't see any significant benefits to using pure nitrogen to inflate your tires...I keep a portable compressor that you plug into your power outlet to 'top up' the pressure on occasion.
What does benefit tires? Maintaining proper air pressure, regular rotations as per the maintenance schedule & proper wheel alignments (I get a 4 wheel alignment with every set of tires I install).
I set all my tires at 33.5 PSI (all seasons & winter sets), I get fantastic fuel economy, even wear & a comfortable ride. IMO, 35 - 40 PSI is too high & that will result in uneven wear or less traction long term.