A long, long time, I decided. Twenty-five years, maybe more.
In a ride-a-bicycle sort of way, my mechanical and electrical skills returned quickly enough, but installing that CB radio I got for Christmas made two things painfully obvious.
First, my aging frame doesn't bend around corners as readily as it used to, especially after four hours in a 40° garage. And second, most of what I saw under the dashboard I didn't recognize -- all those handy grounds, mounting spots and firewall pass-throughs I remember from cars of the '70s and '80s were gone.

Setting the antenna mount in place was simple, but I hit a wall -- the firewall -- when I looked for a way to feed the antenna cable into the passenger compartment. Frustrated, and not wanting to drill a hole in the firewall, I ended up poking a pointy probe through a large boot and (with my wife's help) bringing the coax in next to the brake-pedal pivot.

I managed to hide the connector box up under the center of the dash, securing it with zip-ties to a bundle of wires behind the console. The handset hangs from a clip to the left of the HVAC controls.
In the end, the work wasn't difficult at all. At times it was downright maddening, but I'll chalk that up to unfamiliarity and rusty skills. Anyway, the result was a clean install, if I do say so myself.
But does it work?
Yes and no -- or not yet, anyway. Fifteen methodical minutes with a multi-tester gave me continuity in all the right places, and a quick click of the radio's volume control proved that it's got power.
I won't do a comm check until after I tune the antenna to the radio. Since it was past dusk by the time I finished today, I'll head over to a nearby school parking lot in the morning, hook up the SWR meter and do some fiddling.
I'm cautiously optimistic -- we'll have to see how it goes. Like I said, it's been a while.