Gain Staging Concern

Hello all. So regarding this whole gain staging thing… My question is… Is this something I need to concern myself with? I’ve recorded the lead vocals in a Cubase project file, for my first vocal album that I’m working on. Do I need to turn down the fader and/or object volume and make sure that the track volume is below 0dB, etc. [before mixing the vocal file down]?
After mixing it down, my plan is to import the vocal file into another Cubase project file (where the other instruments are). And when I mix down all these tracks (vocals and instruments) that are here in this particular Cubase project file, do I need to turn down the faders and/or object volumes and make sure the master bus is below 0dB, etc.?
I plan to get somebody else to do the mixing and mastering for me.
Thanks in advance for your help.