It all comes down to what you feel comfortable with really.
I started keeping fish back in 1976 and have built up my own stratagies on what has worked for me in this time, mainly keeping marines, and in the Uk having a 6,000 gallon koi pond.
With regards to trace elements, this is a very important factor and should be added weekly irrelevant of water changes, especially where salt water is concerned, this is in the main due to the massive difference in salt quality from manufacturer and from bucket to bucket, which again brings me back to disturbing the natural eco and bio system that you tank has built up. And also remember modern RO units take every single trace element out of the water you are putting in your tank, so if you are keeping fresh water especially, you are actually in part removing a lot of goodies from your system and replacing it with raw water, so the addition of trace elements becomes an even greater importance.
But with this debate must always come one important thing, and that is you do what you feel comfortable with.
Bets wishes
Michael
www.aqua-digital.com