Part Two: The product · Trouble and change
Saving only on request is simpler to build. A crash, a timeout or a closed tab then throws away someone's work.
A pharmacist spends forty minutes writing a careful reply to a complaint in a support tool. The phone rings. When they come back the session has expired, and the product shows a login page. After logging in, the reply box is empty.
By the product's own account, nothing went wrong. Sessions expire for security. The text was never submitted, so there was nothing to save. Each rule is reasonable. The pharmacist still has to write it all again, worse and angrier, and from then on composes long replies in a separate document and pastes them in.
That last part is the real cost. A person who has lost work once stops trusting the product with anything unfinished. They build their own safety net outside it, and the product becomes the place where finished things are pasted in.
Losing work is easy to build by accident, because it happens in the gaps: between typing and pressing Save, between two devices, between going offline and coming back, between a form's first page and its last. Each gap belongs to no feature, so nobody owns it.
Google Docs closed the first gap in the plainest way. There is no Save button. What you type is kept as you type it, and a small note says so. People who grew up with it find the idea of losing a document strange.
The same holds for work done in the field. An engineer filling in a job report in a basement with no signal should find it waiting, complete, when the phone reconnects.
Therefore:
Keep what people type, upload and arrange from the moment they do it, without being asked. Hold it through timeouts, crashes and lost connections, and show quietly that it is safe.
In practice. Start a long form in your product. Halfway through, close the tab, or turn off the network and submit. Reopen it and see what is left. Do the same on the three screens where people write the most.
Goes with. This is the product's half of UNDO ALMOST EVERYTHING (54). People believe the "saved" note only if the product keeps to HONEST STATUS (82). It matters most on a phone with a poor signal: WORKS WHERE THEY ARE (47).