Of course DCA can be done only if you have a steady source of income or money. I think the best time to do DCA is when the market is falling, because where you buy, if the price goes down from there, you have the opportunity to buy more.So along with money, a suitable market is also very important. Bitcoin price also plays a very important role in DCA
There is no denying that money is necessary to do DCA, whether you have a large amount or weekly or monthly it doesn't matter. You can take advantage of DCA only when you have the opportunity to make frequent purchases at lower prices.
Even if you don't have steady source of income you can still invest on Bitcoin using the DCA method, actually I know that steady source of income could also serve as a propelling factors that fuels the accumulating process of Bitcoin but however saying that DCA method is only meant for those that has a steady income will be indirectly saying that a less privilege cannot be able to accumulate Bitcoin, actually Bitcoin investment doesn't only give room for the rich but also to those who doesn't have much money to invest. So let's not miss Understood DCA method for a normal investment method were you will like to have enough funds and steady income before you could invest on Bitcoin but DCA method work contrary to that.