DCA method should be done in such a way that only money has to be invested in Bitcoin, and this investment has to be for a long time. There is no thought of selling bitcoins from this investment. But usually this Bitcoin DCA method will follow the basic needs of the family and with the extra money, because the more the investment, the more profitable it is because in the future the price of Bitcoin will surely increase several times more than the current price. Note that those who have done the DCA method since 2013, and have played holdings have accumulated and held the highest Bitcoins ever. So if you want to hold Bitcoin then you must hold Bitcoin for a long time and keep investing regularly.
I don't really think people had practiced dca during 2013. Even a lot of people didn't have the idea that Bitcoin would continue going up to what it is today. A lot of investors or holders from 2013 sold more of their Bitcoin and had less, only a few were lucky enough to have a good amount of Bitcoin in their wallet till today. However, dca does not require much evaluation and analysis. It is easy to plan, a certain percentage should be removed for dca while the rest go in for upkeep and emergency funds.
The choice to hold our Bitcoin is up to each investor, even as we may discuss whats best for investors in the public thread it isn't a must that all investors should adhere to the idea of holding for long because it depends on our investment logetivity.