For example, interest rates are currently 3.00% and Rho on a $100 call option is +.45, if interest rates suddenly went to 4%, the premium would rise by $.45. Conversely, if Rho for the put was -.45, the put premium would decline by $.45 per share. Of course this assumes the other pricing factors remain constant.
The higher the price of the stock and the longer time until expiration generally means a greater sensitivity to changes in interest rates (higher absolute Rho values). The cost of carrying a $250 stock position over time will be greater than that of a $50 stock. The longer the time frame the position is held, the greater the cost of money.