you can only install the toolboxes you need. If you are using a user-based license, you can still install your toolboxes later with the toolbox manager directly in MATLAB. Otherwise, you have to run again the installator if you want to install new toolboxes.
Just a limitation I have experienced. If you have a network-license and your admin gives you an installator, I highly recommend you to install all toolboxes you have access to. The reason is that, nowadays there are "MATLAB Updates" for a given version (e.g. 2019b Update 1). If the installator you have got from your IT has no update but you have installed an update (e.g. you have MATLAB R2019b Update 1 and your installator is MATLAB R2019b, no update), than, you cannot install the other toolboxes you could have access to. In that case, you would have to uninstall MATLAB, reinstall MATLAB with the toolboxes and then install in MATLAB the Update(s).