https://tradingeconomics.com/wpl:au:peAs you can see Woodside...

https://tradingeconomics.com/wpl:aue

As you can see Woodside had a P/E ratio of 10 in 2001, and SP about $15.

By the time it had reached ATH's in 2008, the P/E ratio was 40, and SP was $67. This in hindsight was the time to sell.

At the moment, Woodside has a P/E ratio of 6. It's never been lower than that. SP currently $29. This probably is the time to get back in.