Always
I have a plotter, and sometimes run two. However, I ALWAYS have paper charts, and use them hourly. When underway, I keep a deck log, where the position, speed, and course are noted every hour, and on the hour. If a course change, etc, occurs in the interim, it gets noted at that exact time. Whenever a position is marked, I go to the paper chart, and draw it there also. It is notoriously accurate, with few and minor deviance's.
I do this for a few reasons. Electronic discrepancies, and a general distrust of their "infallibility". And I use my sextant as well during this.
During a night crossing, which I commonly do, this is a very reassuring practice. When I get a few shots, and two or more lines of position, and they intersect on the chart as they should, it warms my heart.
I do realize that plotters and GPS are incredibly reliable. However, just last year a 60' steel sailing boat was knocked down, shipped in something like 600 gallons of water, and the ENTIRE electronics system was fried. They were right back to the square rigger technology of a sextant, and a paper chart.
Another reason for charting this way is thus: IF a man has a catastrophic equipment failure, and a radio works, maybe even the handheld, and you give out a mayday, if you have your position, speed, and course noted, the Coast Guard is very efficient of plotting your course from last known position to help.
As apposed to "Mayday, mayday, mayday, we left the Cape Fear approaches last night about ten o'clock heading sort of towards Charleston".
It may be a cold and lonely night. Or worse...
One more thing while I'm thinking about it. I learned celestial navigation from an old Norwegian sailor, one of them that has "been there, done that" types, that taught me the single most important thing on a sailing boat is navigation. Because you can do absolutely everything by the book; and still end up dead. But if you're a good navigator, at least you'll know exactly where you were at when it happened.
