Some of the doors have super cool cracked paint revealing the colors of yesteryear in the crevices. Now a less cool word about that gnarly paint job: paint produced prior to 1978 will likely be lead-based. This isn’t the end of the world; it just means that we have to treat it properly to avoid exposing ourselves, our children, or our pets to harmful lead.
You can take one of two approaches to mitigating the lead paint issue, either test your paint for lead with an easily accessible home test kit, or assume the worst and seal the paint with either one of the specific encapsulating paints available, or seal with a clear sealer like polyurethane, dewaxed shellac, or spar varnish (for outside projects). I applied two coats of shellac to our project. The main purpose of sealing is to avoid any paint chips or dust from coming loose, which is how the lead paint becomes dangerous, through ingestion or inhalation.