Checking dd's progress is very useful. Its tells you how much data has been written, what speed the read/write operation is going at and how long its been going for. Most importantly of all it tells you something is still happening, which is much nicer than sitting at an empty terminal with your fingers crossed.
There are two ways to check dd's progress.
The first one is to use the status=progress option when running your command. See here for advice on using the bs command to speed up your dd.
Already running the command? Don't fear.
If your command is already running, open a new terminal and try running sudo kill -USR1 $(pgrep ^dd). This should display your progress on the terminal running your dd command.