There is no need to charge every day, however frequent top-ups help maintain the life of the battery.
Electric cars car be set to charge at defined times
With a Smart meter there are alternative electricity tariffs available. Of particular note are the half-hourly ones where the price varies for each half hour.
Demand varies during the day, with the peak in the early evening and the trough around 3 A.M. in the night.
Join Octopus Energy and get £50 off via this page. We also receive £50 which will help this site. Octopus offers a range of tariffs including pricing by half-hours and night-times.