I am trying to figure out how many pitchers I need and what their DUR and STA have to look like for me to be sufficiently prepared to cover enough innings going into the season.  I know DUR connects to how often a guy can pitch and STA connects to how many pitches he can throw in an outing, but is there any way of translating this to the total DUR and STA ratings I need across my whole staff?

Going into free agency, the pitchers I am planning to use that I currently own have these numbers:

DUR / STA

32 / 93
28 / 91
30 / 74
23 / 68
20 / 61
72 / 34
79 / 29
58 / 17

I also have offers in on a couple of relief pitchers but have not made offers to any starting pitchers yet.

From what I've read, I think I need at least one more starting pitcher and maybe two... but at the same time I don't want to buy way more innings than I need.

So:

1. Is there a DUR/STA rule of thumb for when you know you have enough innings for your staff to stay fresh throughout the season?

2. How does DUR connect to the percentage of games a pitcher can appear in?  Does the 30 / 74 for the third pitcher in the list mean that he could throw 74 pitches per game if he appeared in 30% of the games?

3. Once you have built your staff, how do you decide on pitch counts?  For example, I know the guy with 74 STA can throw more pitches than 74 per start based on his stats from previous seasons - but how many more assuming he is in a 4- or 5-man rotation?

If this is all covered elsewhere, feel free to point me towards the right discussions.  Any help is greatly appreciated!

That's a difficult question to answer because a lot of it depends on the QUALITY of your staff.   I have two very similar staffs in Mantle and Foxx.   The DUR/STM totals are 424/722 in Mantle and 451/671 in Foxx.    For league averages, Mantle is .04 higher than league average in WHIP and .28 lower in ERA.    Foxx is .12 and .29 lower.   I play in a hitter's park in Foxx(Albuquerque) and a pitcher's park in Mantle(Honolulu).   Number of pitches per game is 139 in Foxx(3 below league average) and 144 in Mantle(3 above league average).  Now, with all that data, here's the point:

I'm really struggling in Foxx to keep a couple of RP at 100% at all times and giving my starters 1 day at 100% before pitching again.   It's not a problem at all in Mantle.

So, in my opinion, you probably need a staff to be constructed more like my Mantle team.   425/700.    With that said, I can guarantee someone is running a 500/650 staff and having no problems at all.

So you just look at the sums of the two - OK, I'll give that a whirl.  Thanks!

What about pitch counts in the manager's office?  Is there an easy connection between STA and pitch counts?

Kinda got off track there.   A good staff will get outs quicker and need less DUR/STM.   A bad staff will need a lot more.    As for your questions, I think I covered #1.

2.  No.   30/74 can throw about 70 pitches every 4th day.   At best, he gets in 25% of your games.   Someone has a formula but I have no idea what it is.

3.  I start with recs and adjust.   For the most part, a 74 stamina will end up at 70/80 for me.   But, if his DUR is low, I'll lower the PC so he can pitch every 5th day.  If it's higher, I might increase it.  

I wouldn't say I just look at the sums but, for the most part, they tend to end up in the same ballpark every time.    I generally have 7 starter/long relief types(low DUR/high STM), 3 short relief types(high DUR/low STM) and then add a couple of pitchers based on talent alone.

The formula for starting pitchers I've seen is 1.3 * ST = PC.  That being said, I don't do anything like that formula.  My baseline formula for SP is:

PC = ST * (DUR/20), rounded down, with the max set only 5 above the target.  

In general, that formula  avoids fatigue in a 5-man rotation.  That said, I don't ordinarily let my 32/66 guys throw anything like 105 pitches; they'll recover in time for their next start but they'll get their brains beat in in the 6th and 7th innings before coming out due to in-game fatigue.  For high-DUR starters their PC depends on how good they are.

For relievers I pretty much always run PC < ST; my staffs tend to run a lot of appearances with guys pitching to just a few batters but being ready to go multiple days in a row.

I have no evidence that this works any better than anything else; it's just what I do.

Interesting stuff guys.  Is there any evidence that pitch counts / IP go into career decline numbers or will they "refresh" annually in the off season? 

PC/IP are directly related to durability, stamina and effectiveness.   And you can set PC.

I didn't give enough information on my question.  Let me give you an example:  I have a pitcher 32/90 who I run in the 125-130 pitch range.  He will get back to 100% on three days rest and be at 100% for a full day prior to pitching again.  He's been getting around 250 innings per year.  Will he decline at a younger age or more quickly than if I were to reduce his pitch count to 115-120?

My question basically is "Is there any evidence that the sim looks at career fatigue over several years, or does it just seem to go year by year?"
 
I assumed the later, that's why I pitch him as much as I do.  I did notice early on that not being at 100% for a day leads to fatigue/performance issues, so I make sure to get all my starters that full day at 100.

And thanks for taking on these questions and helping us noobs out.
And I apologize for piggy-backing someone's question, but I thought this was pretty related to that original question.

There's no evidence that usage affects decline in ratings.    So, yeah, if your guy can pitch how you want to pitch him now, don't cut back out of fear that he'll decline quicker as he ages.

Quick look at the OP and the existing ratings. You need two more guys with 75+ DUR ...or 3 more guys in the 60 range DUR. That should keep a 5 man rotation fresh.

My quick rule of thumb for starting pitchers is if the STA + DUR = 100, the guy will toss about 200-ish innings per season in a regular 5 man rotation. 

There are of course other factors... ballpark, defense, AL, NL, how good the pitcher actually is, etc, etc, etc... but I've been using that as a very rough guideline for a pretty long time and its served me fairly well. 

And to be clear, I use this as a rough guideline. Its most certainly not exact, but nice in a pinch without having to get out the abacus.