When does a team bring in veterans?

[A Future of Stevens]

Disclaimer - I anticipate very little traffic on this topic as it is labor day, but I got lucky on drawing a shift at work and I am very bored so here it goes. Also this is in general, not specifically aimed at the Celtics.

So with all this talk of playing the rookies to develop their skills, or letting rookies compete for minutes I got to thinking. At what point is it a sound strategy for an organization to actually invest resources in a veteran? And let me be clear, I am not talking about a KG level veteran on the Twolves where they average 15ish mpg and put up 3pts/4rb. I mean an actual 26-35 year old who could come in and play 20-30 mins and fight for the top 8 rotation spots. I guess the argument of this boils down to two arguments.

1.) Veteran leadership can help make the young players better pros by showing them the correct way to win, and pushing the young guys to be a better player in order to actually get playing time.

2.) The presence of said veteran can eat into the blue chip prospects reps on the court, thereby stunting the growth of that prospect. Some rookies need to be given a longer leash for them to really find their game, even if it is kind of ugly in the beginning.

So when during a rebuild do you begin to acquire these types of players? From the beginning? Or once the player has established that they can be the foundational piece of your franchise?

I rest somewhere in the middle of this discussion personally. I think that while the addition of players like Thomas and Turner and Amir may have impacted the growth curves of some of our young players (Smart or Kelly,) the good probably outweighs the bad. The addition of these veterans allowed our players to establish themselves in a winning environment. But this is mostly irrelevant due to the highly unique situation the celtics are in (having their forthcoming high picks untethered from the teams performance.)

I guess a counter point could be the addition of Ibaka to the current Magic core while they have a young prospect like Gordon who should be playing at the 4. Will Ibakas presence hurt his development? Or will it help bring him along?

PS- Lets try to keep this thread from spiraling into a flame war or hurling claims of ulterior fandom at one another.  Also sorry about any rushed train of thoughts, but I wanted to get this in before I have to scrub in for surgery. All the best, and happy Labor day!