Shares of memory chipmaker Micron Technology (MU -1.75%) have had a tough few months. The stock closed at a record $1,213.56 on June 25 and is around $715 as I write — still about 40% off that high.

After a slide like that, most investors wonder when to buy. I’ve called the stock a buy more than once this fall, and I still think it’s worth buying at today’s price.

But when a company’s profits can swing as much as Micron’s, I think it’s just as helpful to decide beforehand when the stock would be too expensive to hold.

For me, that level is around $1,050 a share, or about 47% over $715. Here’s how I got there.

Image source: Micron.

The estimate could be too high

Micron’s non-GAAP (adjusted) earnings were $75.52 per share in fiscal…