What has been your costliest mistake in this hobby?


For example :I recently learned a hard lesson- I accidentally ran voltage thru my $3000 MC cartridge (kiseki purple heart).  I have a TT with 5 prong connector and a phono cable with a 5 prong connector.  I accidentally swapped where they plugged into and ran electric thru the tonearm into the cartridge.  It was a stupid - not thinking- hasty mistake. When I corrected the problem the cartridge was fried.  An avalanche of four letter words followed!

So what has been your biggest and/or costliest mistake?
polkalover
I buy albums off of Discogs and didn’t notice that this one album was warped. Put it on my turntable and my JICO (Shure) VN5xMR stylus snapped like a dry twig. I was crestfallen....





@tinear124. I’ve got one that is similar. I was replacing a blown woofer in a set of “expensive” speakers. Removed without issue with a powered screwdriver... then upon reinstalling, the screwdriver slipped and yep... straight through the woofer. There have been a few others, mostly along the lines of spending too much money on cables etc... but the screwdriver through the woofer stands out.
50K in the red and counting, but each time I set aside solitary time to listen, I get goosebumps, especially if the tracks are well recorded. 

40% of that was in retrospect unnecessary, but I remain convinced the cash was better spent than some guys I know who spent/spend similar coin on drugs/booze/women/poker/super bowl tickets etc.

Although I must confess, women sometimes I can almost understand.
Lost a pair of maggies 1.6 which my cat thiught to be giant scratching post .