I, too, need to be selective in the solids that I purchase as my money tree I planted in my back yeard many years ago never grew <img src='style_emoticons//laugh.gif’ border=’0′ style=’vertical-align:middle’ alt=’laugh.gif’ /> !
Because of this, I don't look at whether it is a current release solid or an older one, but I just purchase the ones that really strike me as ones I really like (although I suppose you could make an argument that they all do <img src='style_emoticons//tongue.gif’ border=’0′ style=’vertical-align:middle’ alt=’tongue.gif’ /> )!!
I would think that it would be a good idea to purchase the current limited edition, store exclusive solids when they are currently available so you do not need to pay a premium later as it seems that these tend to sell for a lot more once they are only available on the secondary market.
I have found that the general releases can be purchased for less that original selling price for the next few years after their release (do you have a Cosmetics Company Store near you as they tend to have general releases at really great prices – there is a listing of these stores on this site).
On the other hand, the older solids can also continue to rise – one never knows what the solid market will do! As noted in past posts, beginning in January the secondary market seems to rise, but historically has come back down in the spring, so you may want to wait it out until then for your purchases.
I am anticipating to hear what the “seasoned” collectors would say about your question … <img src='style_emoticons//biggrin.gif’ border=’0′ style=’vertical-align:middle’ alt=’biggrin.gif’ />