When you install the Standard you get a demo period for the Extended, so you can see whether or not you need it before you have to buy it.

DG

All the samples, both Standard and Extended, are automatically installed. If you decide after the demo period that you want to purchase the Extended, you can do that, and you will get a permanent licence. If you decide that you don't, the Extended will just disappear from your sample browser.

DG

 If you look at the Sample Content listed on the web page, you'll see which articulations are in standrad and which in extended.

 That's because you can't buy the extended if you don't already have the standard.  Thus your choice at this point is Standard or both.

@BasariStudios said:

Bill, the problem is that Extended is not even for sale, only Full and Standard which is kinda Confusing, Extended lists as inferior to Standard and also there is no list for Full. Thanks

Full is the same as Standard+ Extended. In any case, the Extended on its own would make no sense.

Edit: Bill got there first. [:D]

DG

Bundles provide major discounts over getting collections individually.  Depending on funds, you might want to consider a bundle of AP Strings I and II, assuming you have decided to go with AP Strings.

As for purchasing standard and/or standard and extended, the dynamic articulations in the extended library are particularly valuable in reaching more lifelike emulations.