I'm afraid I don't agree with that Doug. The great thing about Phase1 is they allow you to stay current at a reasonable price once your in the game.
With an upgrade cycle of 2-3 years if you were to skip a cycle the chances of a failure increase dramatically. Factoring the cost of one failure into the mix the upgrade amortized over that cycle is insignificant.
Of course if the MF gear is not your primary producer of income that changes the circumstances entirely.
I think upgrading is a very hard process to pin down. Obviously!
There is something to the upgrade process as a financial consideration and investment protection decision. Example: Sometimes, there's a very aggressive upgrade price on a new product from your current model. If your model is more than 1 generation back, this could be a very temporary situation and the advantage may be soon lost (forever).
So, some real thought has to go into are you someone who has a product that does exactly what you need it to (as opposed to what you might want it to) and pre-determine that you are typically going to run with that product for 5, 6 , 7 years? (very common with digital back users)
Or are you someone who "likes to stay current" or someone whose photographic workflow and needs change more frequently? Or are you someone who is capable of completely losing your head and getting very juiced over a sexy new product? Probably the majority of this group here...
In any case, it pays to keep an eye on the offers. But here's a couple examples of how someone might miss out if they're a more regular upgrader:
In 2009, if you owned a Leaf Aptus 75 or a Sinar 75 (both valued at about $8K - $10K end user to end user street), you could receive $20,000 credit towards a P65+. I don't have firm upgrade values today on this same configuration, but my sense is that it will wind up around half that. And while the P65+ pricing has been reduced, it still will likely cost a good $4K - $6 more for the same transaction.
At the same time, a P45+ was worth $25,000 in trade value towards a P65+ (net $14,990). Today, the net is $18,144.
So sometimes, especially when products have been out more than a couple years, there are critical junctures where they shift from a great deal to a so-so deal.
Newer products upgraded from still current or last generation products are usually pretty stable in terms of the pricing from launch forward a good while (especially with Phase One). But if you're holding a product that is more than one generation back, it is good to be alert for the right timing.