(No, I have not been thinking about this for 2 months)

You want to measure your success.
Yes, I can see the logic of measuring one stock against its own performance, but how do you even do that? Easiest is compare with if you bought all tranches on first buy date (=buy and hold), but that doesn't reflect reality that you didn't invest (or have) that amount the. Or, you can compare with the most amazing combination of buy-low sell-high repetitions, but that not realistc because (a) you are investing, not trading (b) 20/20 hindsight buy low sell-highs will EASILY outdo any human without a time machine.

There er two other things you can measure agaisnt.
1) how well other buy-and-hold people are doing
2) how well you are doing compared to what you would have donew (term deposits, bonds)