Do you ever look back on your once-loved images and ponder ‘what the heck was I thinking of when I created that’? This may come as a surprise but it is actually a healthy sign of growth, for the following reasons;
A weakening emotional connection. At the time of taking we attain a personal bond to the image, built from experiences at that fleeting moment plus the excitement of the result. As time passes so too may the emotional connection. Some that have a strong back story may survive (and remain favorites) but others will likely fall by the wayside.
Increasing standards. As we continue to hone our craft we should hope that our standards and artistic impression will improve. What was once an image that fully represented your style and technical expertise may now fall short.
That does not mean that all of our older images should be deleted - far from it, but each should be re-evaluated periodically. Those that have retained an emotional connection (which will likely be passed on to viewers), tell the story and meet your quality criteria will remain winners.
However, you should feel empowered to remove any from your portfolio that do not meet your currents standards, comfortable with the knowledge that you have moved forward as an artist. A periodic cull of sub-standard images not only strengthens your overall pool of work but will also raise your own satisfaction level.