[General] Unused RS-485 REciever inputs - PU or PD?

I am working with an SP490E - RS-485 driver/receiver. I am looking for feedback on what to do with the unused Receiver Inputs, do I tie them high or low? The data sheet states the recievers are equipped with a "fail-safe" guaranteeing a high state if left unconnected. This PCB is not cramped for space so PU's would not be a problem. any recommendations from the design community?

Data Sheet:
The receivers for both the SP490E and SP491E have differential inputs with an input sensitivity as low as ±200mV. Input impedance of the receivers is typically 15kΩ (12kΩ minimum). A wide common mode range of -7V to +12V allows for large ground potential differences between systems. The receivers for both the SP490E and SP491E are equipped with the
fail-safe feature. Fail-safe guarantees that
the receiver output will be in a high state when the input is left unconnected.

If you are designing for production you should be aware that all compatible variants of this receiver is not reverting to high state if unconnected. I normally use pullup and pulldown resistors on all inputs to define the polarity when the receiver is floating/idle. We normally use 1k resistors, this will give you 300mV input signal when terminating with 120 ohm, at 5V supply.

This undefined polarity may give you a problem when switching direction on the RS485, in half duplex mode. If the input is unused, the pullup/down resistors does not draw any extra current with no 120 ohm termination.