Ever tried changing batteries of your computer?
The sad truth is that you cannot simply exchange the battery of your Suunto diving computer. After several dives to 50m, the pressure has squeezed the last bit of air out of your battery compartment. At the surface, there is a de-facto vacuum inside, making it impossible to open the battery compartment by using a screwdriver or coin. If you still try to do so, you will certainly destroy the lid of the battery compartment (no big deal), or, even worse, a part of the housing (in which case you killed the entire computer).
So here is how you change batteries. Go to your Suunot Dealer and buy a replacement lid. These come with the battery included. At home, you take a power drill, and drill a tiny hole in the lid of your computer. It allows air to enter, and you can remove the lid very easily with a crew driver. Then you insert the new battery, and new lid, finished. The trick is to sacrifice the old lid, but ensure that you do not break of any notches from the housing.
And next time some Suunot salesmen tries to explain to you that their computers are "user serviceable", show them your finger.