What real-life investment event do most calculators fail to model?

I started building Investment Journey Simulator because I kept running into the same problem with long-term investment calculators: most of them assume the journey is almost perfectly smooth.

You invest the same amount every month, choose an expected return, pick a time horizon and get a final number.

But real life rarely behaves like that.

Someone might:

• lose a job and pause contributions for a year

• restart later at a different amount

• increase investments after a salary change

• make a large lump-sum investment

• withdraw money unexpectedly

• start an SWP

• rebalance after a major market move

• add a second investment midway

• change goals completely after 10 years

And sometimes several of those happen in the same journey.

What became interesting to me was not just the final portfolio value, but how the timing and sequence of those decisions change everything that follows.

For example, pausing an investment for two years early in a 25-year journey is very different from pausing it for two years near the end - even if the amount not invested is exactly the same.

That is the kind of problem I have been trying to model.

Before the public launch, I’m curious about something:

What real-life financial event have you experienced — or seen someone experience — that normal investment calculators usually fail to represent properly?

It could be something simple or unusual:

• career break

• parental leave

• moving countries

• buying a house

• supporting parents

• education expenses

• irregular bonuses

• early retirement

• partial portfolio liquidation

• inheritance

• business income changing month to month

• tax changes

I’m especially interested in combinations of events, because those are where the modelling gets much harder.

If there is something obvious I’ve missed, I’d genuinely like to know before I consider the simulator “complete.”