Problems with scaling have been the biggest timewaster in my career:

1. In some large businesses I've worked in, so many people have been hired that some systems and processes have wound up being controlled by entirely different people from the people who need them. So coordination between people and waiting for people who have little to no incentive to do the thing they're being asked to takes up a large part of the working day.

2. In other businesses, a large fraction, or even a large majority of the employees have had no discernible job except to talk and write about the job performed by the few people doing an actual job. So a lot of time in these businesses would be spent dodging meeting invitations, rejecting grand ideas about revolutionizing the business with AI on the blockchain, saying no to "if you could X, that'd be great" and generally reminding people that they're not in charge.

The great thing about these problems is that you're not very likely to have them in a small startup, but if you decide to grow the organization later, you'll need to be very vigilant about how you scale.

In my experience, the biggest weekly time sink tends to be work that sits between teams rather than inside a single system. Things like manually reconciling data between billing, support, and ops, or preparing the same reports in slightly different formats for different stakeholders. These processes usually start small and “temporary,” but scale quietly as the company grows. The trade-off is that they’re hard to automate cleanly because ownership isn’t always clear. Curious whether the pain you’re seeing is more about fragmented data or about human approval loops that automation alone doesn’t fully eliminate?

As a solo person running a website: Accounting and invoicing.

Even for a tiny outfit with quarterly invoicing, it's tedious.

Timesheets.

The accounting pain nicbou mentioned is real. Bank reconciliation seems simple - two lists, match them - but then you hit timing differences where something cleared on different dates in each system, or description mismatches where the bank shows "PAYPAL *ACME" but you recorded "Acme Ltd - Invoice 4521".

Transaction categorisation is arguably worse because there's no universal standard. What one accountant calls "Office Expenses" another puts in "General Admin" - both correct for their context. Any automation that works for one client's books tends to break when you switch to another.