A few inquiries a2ensite and systemctl reload apache2

Hi,

Do I have to do a a2ensite mysite.com every time I make a change in it's .conf file in sites-enabled ?

Do I always have to follow it with 'systemctl reload apache2' ?

Can I do..

a2ensite mysite1
then
a2ensite mysite2
then do a systemctl reload apache2 or does it have to follow each indiv site entry?

Do I have to do a systemctl reload apache2 after I make any changes in any of the site's public_html files ?

What is the best definitive way to finish messing with files in websites so that apache2 recognises the changes ?

Thanks

oz