How many classes a week should a beginner take?
One or two. A brand-new fencer gets almost everything they need from one good group class a week plus one open-fencing or footwork session once the club allows it. More than that too early mostly buys sore legs and burnout, not faster progress.
The typical progression that works: months 1-3, one class weekly. Months 3-12, two sessions, one class, one practice where they actually bout. After the first year, if they're hooked and maybe competing, three sessions plus an occasional private lesson is the sweet spot most competitive juniors settle into. National-level teens train four to six times a week, but nobody starts there.
Two signals tell you it's time to add a day: they're asking for more (not you), and their coach says their basics are solid enough that more bouting will help rather than groove bad habits.
If the budget only allows one session a week, take it, consistency beats volume. A fencer who never misses their weekly class for a year will beat one who did a three-day-a-week burst and quit in March.