Been controlling humidity for perhaps 15 years.
No more eye seepage and ears look very clean. Not like before.

The only other thing that changed is perhaps their diet is better.
Without a dehumidifier, the air conditioner and heater can be used
simultaneously to reduce humidity, when needed. Humidity meters are less
than $10 (US) at the local megastore. I usually keep the humidity at
about 50%. In the 60s is too high. Controlling humidity also prevents
fleas from reproducing.