I want to pay 5 years Class 3 NICs from 2017/2022.
Apart from cashflow, is there any advantage to starting to pay by monthly DD in 2017 instead of waiting until 2022 and paying a 5 year lump sum? Does the amount increase if you pay in arrears?
The amount is fixed at the in year price for 2 years after the end of the year so 2016-17 needs to be paid by 5 April 2019 to keep the current price. After then it increases to the price of the year when you pay. Best to keep the cash in an interest earning account until the last moment, falling under a bus would mean the money is wasted.