7 Expensive Mistakes Substitute Teachers Make (And How to Avoid Them)

Some substitute teaching mistakes cost you money. Others cost you reputation. A few cost you both.

Here are the biggest mistakes subs make - and how to avoid them.

Mistake 1: Taking Jobs You Shouldn't Take

The trap: You need money, so you accept every job offered.

Why it backfires:

• You're miserable in subjects/grades you hate
• Poor performance = not requested again
• You burn out faster
• Some jobs cost more in gas than they pay

The fix: Calculate your actual hourly rate including drive time. A $70 half-day job 45 minutes away might pay less per hour than a $100 full-day job 10 minutes away.

Be selective from day one. Saying no to bad jobs leaves you available for good ones.

Mistake 2: Not Reading the Sub Notes

The scene: You arrive, don't read the notes, wing it. Turns out there was a fire drill scheduled, modified schedule for testing, and three students with specific medical needs.

Why it's expensive: Teachers don't request subs who don't follow instructions. Office staff remember chaos.

The fix: Always read the sub notes. Twice. Before students arrive.

Bonus: Notes often tell you which students to watch, where supplies are, and if there are any "gotchas" for the day.

Mistake 3: Losing the Job-Hunting Game

The mistake: Relying on Frontline's email notifications and manual checking.

Why it costs you:

• Best jobs fill in minutes
• Email notifications are too slow (10-20 minutes)
• By the time you check, good jobs are gone
• You waste 1-2 hours daily refreshing and searching

The fix: Use smarter systems. Push notifications are instant. Filters eliminate irrelevant jobs. One-click acceptance beats the other subs.

Calculate: If you spend 10 hours per week job hunting, and you earn $20/hour when actually working, you're losing $200/week in opportunity cost.

Mistake 4: No Emergency Plans

The scenario: Lesson plans are vague. Or missing. Or make no sense. Students finish work in 15 minutes. You have 75 minutes left.

What happens: Chaos. Students on phones. Behavior issues. Teachers don't request you again.

The fix: Always have emergency activities:

• Reading + comprehension questions (any grade)
• Math review worksheets (different levels)
• Writing prompts
• Educational videos (approved by school)
• Review games

Store them on Google Drive. Pull them up on the classroom computer when needed.

Mistake 5: Saying Yes to Everything the Students Ask

Common requests:

• "Can we use our phones?"
• "Can we work in groups?"
• "Can we go to the library?"
• "Our teacher lets us..."

Why "yes" backfires:

• You don't know the school's policies
• Students take advantage
• You lose control
• Regular teacher comes back to complaints

The fix: Default to "no" or "let me check the notes."

Exception: If the notes explicitly say "students may work in groups after completing X," then yes.

Mistake 6: Not Building Relationships

The mistake: Showing up, teaching, leaving. Every school is just another gig.

Why it's expensive:

• You never get directly requested
• You miss out on long-term assignments
• You don't get the easy days (teachers who know you leave better plans)
• You're always starting from scratch

The fix: Pick 3-5 schools you like. Work there regularly. Learn names. Be consistently good.

Impact: After 3-4 times at the same school, teachers start requesting you. Office staff know your name. You get first pick at long-term assignments.

This pays off: Requested subs work more consistently and make more money.

Mistake 7: Bad Time Management

Common scenarios:

• Arriving late (traffic, couldn't find parking)
• Not using prep period effectively
• Forgetting to sign out
• Leaving mess for next day

Why it matters:

• Late arrivals are noted and shared among office staff
• Unprofessional behavior = not called back
• Small things add up to reputation

The fix:

• Arrive 15 minutes early
• Use GPS and plan route the night before
• Set phone reminder to sign out
• Leave classroom cleaner than you found it

Think of it like this: Your reputation is your resume. Every job is an interview for the next one.

The Cost of These Mistakes

Let's add it up:

Taking bad jobs: Waste 2 hours/week = -$40/week = -$1,600/year

Slow job hunting: Lose 3 good jobs/month to faster subs = -$360/month = -$4,320/year

Poor reputation: Miss 5 direct requests/year = -$600/year

No emergency plans: One bad day = never requested at that school again = immeasurable

Total potential loss: $6,500+ per year

Compare: Sub Hero costs $83/year (Standard) or $119/year (Pro)

If it helps you land just 2-3 extra jobs per year, it pays for itself.

Start Avoiding These Mistakes

The fastest fix: Consider whether your current job-hunting approach is sustainable long-term.

Sub Hero handles monitoring for you:

• Set preferences once (schools, subjects, schedules you want)
• Get instant push notifications
• Accept jobs with one click
• Auto-accept your favorites (Pro)

Result: More time for being a better sub. More good jobs secured. Less stress.

Learn more: app.getsubhero.com

Sub Hero is one option for addressing this. It won't solve everything, but many subs find it helpful for reducing time spent on job hunting.

Plans start at $6.99/month. Works with Frontline Absence Management.