I am planning to change the vinyl liner, so is it better to change the liner in the fall or in the spring before the next season?

Also if I change the liner in the spring, is there any need to put chemicals in the water before closing since I will need to drain it when I change the liner?

Any help with these questions would be great.

Thanks,
Matt.

Pool: IG 16x32; 5 ft average depth; vinly liner.