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I'm still not going to waste money on lithium. It's cheaper to buy a new clock.
But that takes effort to do.
I pay myself $100 an hour for anything I do that I don't enjoy. So, spending 20 minutes finding, ordering, and hanging a $5 wall clock actually costs me nearly $40 by my calculation! So, a lithium battery is easily worth its price to me, if it stays in service significantly longer than the alternative.
Your calculation may be different, if you have a hobby of searching for clocks and hanging them up, then a lithium battery doesn't make sense, you'd probably change the clock before the battery drained anyway!