Hello. I am new to Avast! Pro. I was wondering something about boot scans and full scans. If I do a boot scan, is there any merit to doing a full scan afterwards?
No. avast! boot time scanning is a complete scan.
Welcome!
Awesome. I make it a habit to not use my computer during full scans, so I may as well just do boot scans
Personally I wouldn’t do a boot-time scan aside form it scanning Archives (inert until unpacked) and PUPS (Potentially Unwanted Program), not necessarily malicious.
So it will be slower and it is essentially a special purpose scan, if a detection is made on a normal scan and it can’t be dealt with in windows normal mode.
With a resident on-access antivirus like avast, the need for frequent on-demand scans is much depreciated. For the most part the on-demand scan is going to be scanning files that would be otherwise be dormant or inert. If they were active files then the on-access file system shield would be scanning them before being created, modified, opened or executed.
I have avast set to do a scheduled weekly Quick scan, set at a time and day that I know the computer will be on. If for some reason my system wasn’t on, no big deal I will catch up on the next scheduled scan.
The only reason I can see to run a boot scan is if something shows up during a regular quick or full scan.
I’m a bit more “paranoid” than DavidR I run a full scan once a week and a quick scan twice a week.
I never schedule any scans I start them while I’m sitting at my computer. 
+1