When referring to cash ISAs specifically, you will find that often you can only deposit one sum in a fixed rate. However, the best offers will provide you with the best cash ISA rates and easy access which means you can deposit any amount at any time you choose. Often with cash ISAs you can find rates that apply to balances as small as one pound or ten pounds.

In terms of other accounts, such as unit trusts or investments, you can often receive a plan where you can deposit on a monthly basis steadily. This way you can pay over the entire tax year, as long as you don’t go past your annual allowance limit.