Step 15: Avoid Common Mistakes

The fastest way to save money is to stop leaks. Step 15 is a calm audit of the habits that quietly undo good research: chasing juicy premiums, skipping valuation, ignoring assignment plans, or trading too big when emotions run hot. Catch these early and the rest of the blueprint compounds smoothly.

TL;DR

• Treat valuation as the gatekeeper; no trade moves forward without a fair value and margin of safety
• Cap trade size: 1–2% of capital per option contract; journal every move before and after execution
• Time trades around risk: avoid earnings and low-liquidity strikes that distort pricing
• Prepare for assignment before selling a contract; know how you will manage shares or rolls
• Slow down after wins or losses; a pause beats revenge trading every time

The mistakes that cost beginners the most

Skipping the valuation step

Selling puts on a popular ticker without intrinsic value math is just guessing. Protect yourself by running the numbers in the Wall St Yardie app—cheat using the Wall St Yardie app to anchor every strike to fair value. If your fair value is $60 and the stock trades at $58, a $50 strike might offer yield and safety; a $55 strike might be disguised overconfidence.

Oversizing in the name of speed

Two CSPs on a $45 strike tie up $9,000. If your portfolio is $50,000, that is 18% exposure to one ticker. Keep CSP exposure to 1–2% per contract and total strategy exposure below 20%. Covered calls should match share count only; never add synthetic exposure just to collect more premium.

Trading through noise

Earnings and thinly traded strikes warp spreads. A penny stock with a $0.60 bid and $1.00 ask is not a bargain; it is a trap. Favor liquid chains with tight spreads and skip the week of earnings unless the trade is a deliberate hedge.

No plan for assignment

Assignment is not a failure. It is a predictable outcome. Before selling a put, decide whether you want 100 shares at the strike and how you will manage them: hold, sell covered calls, or exit. Review /blog/step-by-step-beginner-blueprint/blueprint-step-9-assignment for a calm walkthrough.

A quick numeric illustration

You sell one cash-secured put on a company worth $70 by your valuation, with a $55 strike and $2 premium. Capital at risk is $5,500 minus $200 premium, or $5,300 effective. That is 5.3% of a $100,000 portfolio. If assigned, you plan to sell a $65 covered call and collect another $2.50, lowering cost basis to $52.50. The math works because you sized the trade, chose a strike below fair value, and had a post-assignment plan.

Add behavioral guardrails

• Journaling: Log thesis, strike, fair value, and post-trade review. Patterns of overtrading show up fast.
• Cooling-off rule: After a large win or loss, require one trading session with only observation.
• One change at a time: Adjust either strike, duration, or size—not all three—so you can learn cause and effect.

For a deeper list of pitfalls, revisit the broader mistakes guide: /blog/common-mistakes-to-avoid/mistakes-no-risk-management. Pair it with the risk plan ideas in /blog/risk-management-with-options/risk-options-risk-plan to keep emotions contained.

Turn mistakes into a weekly retro

• Pick three trades: one win, one loss, one breakeven. Write whether each followed your checklist.
• Quantify the error: Did you move a strike $2 closer? Did you double size after a win? Numbers make patterns obvious.
• Adjust one variable: For the next five trades, change only one thing—strike distance, DTE, or size—so you can see what helps.
• Share with yourself: Write a three-line summary you will read before placing the next week’s orders. Small reminders prevent repeat slips.

Example retro

Last week you chased a CSP on a fair value $55 stock by selling a $50 strike for $3.00 even though your plan requires 20% distance. Assignment came fast and you froze. The fix: move target strikes to 25% below fair value, pre-stage a covered call exit, and limit new CSPs to one per ticker until the habit sticks. The following week, you sell a $42 strike for $1.60 with cash reserved and a $50 covered call drafted. Stress drops because the plan is written.

What could go wrong?

• Premium chasing: High IV tempts larger size and closer strikes. Mitigation: pre-set max exposure and minimum margin of safety.
• Illiquid exits: Wide spreads trap you in a roll. Mitigation: filter for volume and open interest before entering.
• Assignment panic: Receiving shares without cash reserved. Mitigation: keep cash for the full strike and a post-assignment covered call.
• Revenge trades: Trying to recover a loss quickly. Mitigation: enforce a waiting period and review journal before placing the next trade.

Signs you should pause

• You placed more trades this week than your written cap.
• You adjusted strikes twice after submitting an order because price moved.
• You cannot articulate the fair value for three open positions from memory.
• Your journal is empty for the last five trades.

When any of these show up, step away for a day. Recalculate fair values in the Wall St Yardie app, reread your weekly retro, and return with smaller size until confidence and discipline realign.

Next steps

• Set written size caps for CSPs, covered calls, and protective puts
• Add a valuation step to your pre-trade checklist using Wall St Yardie for fair value estimates
• Create a simple assignment playbook for puts and calls
• Filter your watchlist for liquidity and avoid earnings-week trades
• Journal the last five trades and note any patterns to change