Charge after every use and charge once per month if left idle for one month straight.
Lead-acid batteries need distilled water added over time as the water level decreases. The level should cover the plates but should be about 1” below the very top of the battery or kept at or below the fill line. Always water batteries after charging.
Lithium batteries are clearly more expensive than lead-acid, and the increased cost over the long term may be worth it to have a maintenance free solution. Personal preference is a deciding factor.