Personally, I find temeculaguy’s simple formula much easier: if the house price is rent x 100, it is a nobrainer; if it is rent x 125, look really hard; and if it is rent x 150 or above, it is still in its bubble price.
By this logic, a big 4br house in Mira Mesa that would rent for $2000/month is in its bubble price unless it drops to 250k.
