My goal is to have about 125 domains at any one time, but I am currently above that at about 225 domains.
As a risk averse senior on a pension, I never plan to risk much with acquisition of high value domains or ones with premium renewal rates. I realize that means most of my sales will be in the $$ to $$$ range and I am fine with that. My aim is to sell each domain for at least 4x (hopefully more!) my acquisition/holding cost, and portfolio overall at least break even (hopefully a bit better than that). Ideally I aim to sell at least 10 to 15% of my portfolio per year. I am currently on track with these goals.
My portfolio is mainly in a number of new extensions (space, site, science, icu, top, trade, review, and gdn, and smaller numbers of others), along with 12 .ca, 6 .com, and about 20 in other cc's (mainly co, some pw and me).
I guess my icon should be a piggy bank?
I admire those of you who are into higher risk / much higher return portfolios, and have the ability to close those big $$$$ to $$$$$$ or more sales, but that is not me at this stage in life. I do understand that if you are to have any hope of making a living at domaining you need a significantly sized portfolio of high quality, moderately expensive domain names.