I think you should convert it to fiat immediately because when you go to restock, you will have to pay in your local currency. If you decide to leave the money as Bitcoin then in volatile times like this, you can think of it as an investment. Hopefully Bitcoin will be accepted by many people and its volatility and transaction fees reduce as well so people can actually hold their money in BTC without worrying if their gain has been tampered.
Exactly, I think that bitcoin isn't as good as a way to be part of your revenue because of it's volatility so it's not a good thing to save that bitcoin especially when you're running a business and from what I've heard, it's really hard to run one because you're going to think up of all the costs that you're business will have to sustain, there's upkeep cost, restocking, salary for the workers and upgrading the business and I don't think that bitcoin is up for that business sustain. I'm just talking about what I think works but it seems that you're doing just fine though so I guess you can keep doing that but do be careful as bitcoin's more suited as a means of investment rather than a currency.