Well, that's a toughie: What I try to do is keep my prices constant over the short term, but adjust them during serious price spikes/sags. So for example for the longest time repairs were based on a $600/bitcoin price, which I held from 400 (I was losing money but believed in bitcoin) to 800 (I was making extra money which compensated for the $400 times) but still was paying taxes on the effective $600 rate.
Once it blew past I adjusted my prices to reflect the increased value. Which I thought about for awhile as the miners are now worth more, and since they mine in lite/bit coin one could argue that the end user is making more therefore I should make more on the repair. But there is this weird fairness thing in my head, so I reduce the crypto price to reflect the new value of the coins.
Paying taxes is a bitch on all of this, you have to pay employment+income taxes on the repairs as you sell them (minus costs for parts, testing power, tools, consumables, capital purchases depreciated over an X year timeframe) and taxes in the US have to be paid in dollars, but I'm really trying to see if you can do a fully on board business. Note you have to pay the taxes on the amount received at the time received so if bitcoin tanks and you didn't sell a bit of coin from each repair to cover the taxes you may have to sell a LOT at tax time (in which case you can write off the loss over several years but that sucks a lot) or come up with the cash. This nailed a lot of people in the stock option days, when people got options, the markets crashed, and they found they owed a lot in taxes on their now-worthless stock. Oops.
Then there is taxes on appreciation/depreciation when you sell the coins for money (which you can help with a FIFO strategy vs LIFO although I guess you could do unique lots as each bitpenny is unique but that would be hell on wheels) but using LIFO the ups and downs tend to cancel each other out in terms of net gain. However if you sell a big block you need to pay STCG instead of LTCG on latest assets held less than a year, so choose wisely.
It's complicated but I'm giving it the best go I can. Eventually people should feel comfortable using coins for normal expenses, hopefully by then the tax and accounting ramifications will become more sane.