Trace means very little regurgitation and mild means a little and these are considered to be "normal". Moderate regurgitation can be concerning and severe regurgitation is very concerning.
A baseline echocardiogram can quantify the amount of regurgitation and identify if the leaflets of the valve are healthy. This exam serves as a basis for follow up.
In my patients who have trace or mild regurgitation, I do recommend that they return annually for follow up to listen to their symptoms and listen to their heart, to compare to their previous assessments. Most of the time, there's no worsening of the prolapse or murmur over time.