How to pause a strategy session without losing the board
The safe stopping point differs between games, and finding it once saves a lot of boards.
Strategy games are not built to be played in one long sitting in front of the same screen. They are built to be thought about, left, and resumed. The trouble is that not every game resumes the same way, and that is how people lose boards they spent forty minutes building.
The first thing to identify is whether the game saves state automatically after every action, or only at the end of a round. You can test this in three minutes: make one small move, close the tab, reopen it. If the move is still there, saving happens instantly. If it is gone, the game saves only at specific points, and you need to find those points before you stop.
For games that save at the end of a round, the safe habit is to stop only after the round summary appears. Do not stop midway through a move, even a move that looks trivial. The gap between two moves is the most dangerous place to close a tab, because that is exactly where the state has not yet been written to storage.
The second thing is knowing whether the game saves in the browser or on a server. Browser strategy games without accounts almost always save locally, which means your board is tied to one device and one browser. Move from phone to laptop and the board will not appear, and there is no way to transfer it. Plan long sessions on the device you will keep using all day.
The third thing is avoiding data cleaning. This sounds trivial until a forty-minute board disappears. Clearing the cache is safe. Clearing cookies and site data is not, because it wipes game storage in the same stroke. If your phone offers weekly automatic cleaning, exclude the browser you play in, or switch that feature off entirely.
The fourth thing is private windows. That mode erases all storage the moment the window closes, with no exceptions. It is useful for reading news, but it is the fastest way to throw away an unfinished strategy board. Get used to playing in a normal window, and keep private mode for other things.
Finally, one small habit that rescues many sessions: before you stop, leave yourself a note in your head about the next move, and make sure it is something you can read back in five seconds. A good strategy board is not only the state of the game, it is also the state of your mind. When you return two hours later, that note puts you back in the same place faster than re-reading the whole board.

Goods Sorting Shopping Master 2
Find the Kitten: Spot the Cat