What has been your costliest mistake in this hobby?

@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 .

Letting go of items that now I wish I hadn't....

But what makes sense @ one point becomes senseless later, but one has to live thru that sort of thing to find out... ;)

Oh, well....Another Miserable Day In Paradise....*L*

I forgot this one, but it was almost made right.

I went out into my shop one day and it was cleaned out. This was 6 years ago. My C22, 2 MC240, 4 TTs, 2 Reel to Reels, A foot locker of NOS valves (est value 25,000.)
A handbuilt, 11 band, tube, parametric, EQ with 2 external 3 way crossovers. My stratherarn ribbon speakers.

ALL the gear was packed in foul weather shipping crates.

A lot of tool and other things too.

The insurance paid 56k or something like that, The only big loss was the strathearn ribbon speakers, I couldn't find a source at the time. so they wouldn't replace the 6K or so for them, only depreciation of 2K or something..

BTW know who did it, told them they did it. A kid I helped out. It didn't go well for him. His bad ways caught up with him, sad...

I did ok though, considering.. First and only time someones done that to me..Hurt my feelings... Yup sure did.. Helped raise that kid...Little turd...

Regards