The days of selling handregged domains are over.
Ma'am, you seem like a nice person. Respectfully beseeching you not to offer such a terribly negative opinion that is provably untrue.
All 8k+ our of domains are hand-registered, more than 90% are one-word, and ONLY since registering and selling .work domains in 2017 did we ever cover cost of all renewals for all the .com's.
2018 and 2019 are the first 2 years since building first site in 1994 that we're in the black... wait, wait, AND, because we give modest prices, more of our buyers are now repeat buyers. You can see from SweetestDomains that we offer gorgeous one-word .com's, and almost every one we've ever sold ... was NOT because of marketplace or auction listings, instead, it's due to emails we send directly to .... those people/orgs most likely to be desirous of a particular set of domains (we also tend to buy related domains so that we can give freebies when they buy their fave).
Wise of you to adopt the Rick Schwartz approach of only selling occasionally. The charities we each may choose to support will be very very happy 10 yrs from now.
Cheers.