Stick-up cam not holding charge like it did first year

Hi,We’ve had our stick-up camera for about two years. The first year and a half, we charged it about every six months. This was great! But now, for the last 6 months, the charge lasts barely 3 months. Nothing has changed in our wifi service or common activities that we know of. The settings are the same as when we started. Is this just a sign of overall battery life and we need to get a new battery every 1.5 years or so? Any thing else to consider?Thanks!