Common mistakes when automating a strategy

Leaving out the exit rules

Manual traders often 'just know' when to get out based on feel. An EA has no feel — if the exit isn't explicitly defined, it either never closes the trade or closes it on the wrong condition.

No stop-loss at all

The single most common way an automated strategy turns into an account-blower. Every rule set needs an explicit hard stop, not an assumption that price will come back.

Fixed lot size instead of risk-based sizing

A flat 0.1 lots on every trade means your actual risk swings with every different stop-loss distance. Sizing by a fixed % of account risk keeps every trade's downside comparable.

Ambiguous conditions

"Enter near support" isn't a rule a program can execute — how near? Automating a strategy forces the vague parts of it into specifics, which is often where people discover the strategy wasn't as well-defined as it felt.

Assuming a logic check is a backtest

Confirming an EA's rules fire correctly is not the same as confirming the strategy is profitable historically. Conflating the two leads to false confidence before going live.

No plan for when MetaTrader isn't running

An EA only works while the terminal is open and connected. Running it on a laptop that sleeps or shuts down means it silently stops watching the market with no warning.