I've actually created a business model based on it.
The vhs rental stores were dying left and right. The one i looked into got most of its money from snacks and drinks. The subscription moddel was 75 cent, renting a movie would drop from 3-4 euro to 75 cent. (only 1 at a time) You could keep it for a week, then you would get a call if you could please return it.
The existing customers knew vhs rental was not really a thing anymore. Many visited just for a chat.
I figured one could guilt people into keeping the sub. I wasnt looking to make a profit, just curuous about the puzzle.
Looking at uvb there use to be several afordable manufacturers with good test data but they all closed shop. What is left either doesnt work or is scarry expensive.
The lamps are cheap the coating is hard to develop. Im not sure but it seems if you want to produce it you have to redo the rnd to figure out how.
That just calls for the purchase of 2 copies and the application of the learnings inside. A near infinite source of inside jokes. I know well who I have to make.
If pages arent fast or links are broken i move the url to a different file checked less frequently, when checking those i move what fails to the next file and check that on an even lower frequency (if at all)