Firstly, I would like to start by saying that this is how I calculate XIRR for my portfolio and this may not be the right way to do it. If I remembered correctly, using XIRR to track your portfolio is controversial and there are people who think XIRR should not be used and there are different ways of doing it.
When I just started investing, I do keep track of my cumulative return and CAGR but I feel that the values calculated do not really reflect the performance of my portfolio. Cumulative return do not take time into consideration, so it could be a case of 20% return in 1 year versus 20 years. Without the time frame, there is no basis for comparison.
If we want to take the length of investment into consideration, one option is to use the CAGR. But CAGR only takes the starting and