Antenna length for reciever-only antenna

Hello everyone in the amateur radio community, I got intrested in this hobby a year or two ago, I will register for my exam this summer.

I have an important question, I am building a non-stationary antenna that I plan to put on the roof, keep in mind, not stationary. I will use this antenna for VHF 130 -180 MHz listening, does the length really matter? I know that lenghts are resonant with frequencies, but I am planning to only use this for listening, not transmitting.

Any help welcome, Thank you.