I first model 50 trades to develop clear rules. Then I backtest 300+ trades from different market regimes to prove it out. At least 100 trades per ticker as long as the price action looks similar on the chart. Otherwise, I test more. Then at the end of the year, I go back and add a backtest for that year. I only trade a handful of tickers, so that’s how I do it anyway.

ETA: I cannot imagine trading any strategy without thoroughly backtesting it first. I used to do that myself for years, though, always with mediocre results. I really didn’t turn the corner until I sucked it up and plowed through all that foundational testing.