I have learned a few things about power sources over the years. One, you never want to be on the hairy edge of any power input or output requirement and two, current is additive at times. You will deal with a lot of 5 volt sources to power the RPi(s) and usually any USB hub(s) that you have around, not to mention the monitor and powered speakers. So how do we deal with this?
Make sure that you pay attention to the current draw from the RPi. The USB ports only allow for 150 ma draw and exceeding that value also affects the ethernet port; not to mention the damage that it might cause (there is no overcurrent protection). I would start by only connecting powered USB hubs to the USB ports on the RPi. In that way, you are pretty much assured that you will not be drawing too much current from the port. However, be careful - I have heard reports that there are some older hubs that try to draw the normal 500 ma from the main USB port connection.
The problem with current USB hubs is that you don't know how much current that they will normally provide. The package typically will not tell you what the power supply is capable of delivering. Sometimes, you have to do a little extra research to find out. E.g., when you are standing in the store about to pick up the USB hub, do a check with your smart phone to find out if there are some specs available on the model. A lot of times you will see a 5volt/1 amp power supply for a 7-port USB hub. Do the math, if the spec says that the USB port should supply 500 ma, then there is no way that a 1 amp (1000 ma) supply is sufficient. Finding hubs capable of supplying the spec level current is very hard. I have an old 4-port Belkin hub that has a 5 volt/2.5 amp supply - it has the capability of supplying the specified current on each port with some extra.
If at all possible find hubs that have supplies that are powered by 5 volt supplies. The reason is that eventually you may want to power the hub with a 5 volt battery that would also powers the RPi.
This is a blog mostly about techie things, what I am doing to my apartment network on the cheap, IOT, 3D Printing, Raspberry Pis, Arduinos, ESP32, ESP8266, Home Automation, Personal Weather Stations, Things That Go Bump in the Night, and some side issues that need discussing. Remember, sometimes the journey to an end is as much fun as the goal achieved!
