As most followers of this blog knows, we record our monthly expenses almost religiously. I have little doubt that this is the best way for us to find out how much we are spending every month. Otherwise, without doing this, when would we realise we have squirrelled away enough for our semi-retirement or even quarter-retirement? ????

To keep the monthly updates uncluttered, I have actually divided our expenses into two portions:

1. The fixed, recurring expenses and

2. The variable expenses

And for the past year’s monthly updates, I have been using the amortised fixed expenses calculated on 12th July 2015 as a simple way to calculate our total expenses for the month. Besides simplicity, this method has also helped to minimize the volatility across months.

However, this also meant that the updates aren’t as accurate as they should be. Therefore, to ensure that these updates are as relevant and precise as possible and to …