I've been watching a lot of Day videos to get better at SC2. My main race is Protoss and Day loves the phrase "pylons and probes", meaning you should always be building pylons so you aren't supply blocked, and that you should always have a probe building. I'm getting better at both of these, but is there a point at which you have too many probes and you should just stop building them? It doesn't seem like I've ever gotten to the point that I couldn't build enough units because I had too many probes. But by the end of a game I look at my bases and see a LOT of probes. I also notice that lots of pro players seem to count their probes (or workers) a lot by boxing them all. Is there a point where if I count a certain number of probes I should just stop building them?
So, there is no correct answer to this question.
Traditional doctrine said about 3 bases (80-90 Probes). This is necessary to continue adding to the standard Protoss "death ball" out of 6 Gate + 2 Robo, while adding in HT. Supporting your death ball requires at least 2 bases in mid to late game, and to make the tech transition to HT on 2 base is usually a blunder which will cost you the game. So if you're going for the standard Colossus into HT, you have to have that third base saturated.
More recently, high end Protoss players (oGsMC), have been moving away from the classic Colossus into High Templar and have been moving towards even heavier economic builds (like Colossus Void Ray). Whether these are strategies which favor the more macro centric 1 Gate Expanding Protoss, or responses to the new Khaydarin Amulet nerf (which was announced weeks ago), we're now seeing Protoss players getting 110+ Probes on 4 Bases.
Ultimately, how many Probes you build is a function of what your timing windows are. The question should never be: How many Probes do I build? Rather the question you should be asking is When do I stop building Probes?
Knowing when to cut Probe production is a skill, and that timing is what makes your BO effective.
As each resource patch (minerals or gas) can only handle 3 workers maximum (nearby minerals slightly less than three), and most non-gold expansions have 8 mineral patches + 2 gas, any more than 30 workers per expansion will essentially be a waste. That said, you could build up more than that if you plan on expanding soon so when it finishes you can get a quicker economic boost when you transfer.
And as always, Team Liquid has plenty of theorycrafting on mining.
As I can tell from my experience it's time to stop making probes when you reach 180-200 limit and have 2+ expansions. You'll have about 80 probes. If game is not ended at this moment then:
- research all upgrades you dream of
- replace low cost warp gate units with high cost stargate / robo / templars (so cost of your army will increase)
- slowly replace probe limit with army to have at least 2 fully saturated expansions (about 50 probes)
(in this order)
P.S. I'm really crazy about probe building - unconsciously. And sometimes I have over half of limit as probes. It's an overshoot of course ^_^ If I found myself in such situation then I just send probes to cover a map and die to free up limit.
Well, if you always die when the opponent pushes because you only have probes and no army, then you probably overdid the probe-production.
It's true though that you should produce as many probes as possible (in the early game). A good player will constantly produce probes and have an army just the size to defend an early push.
I'm far from being a pro player, but usually I constantly build probes/drones/SCV from the start of the game, so that I have enough workers to move over to my first expansion when it goes up. With time you'll be able to spot a good worker saturation. When I'm not sure whether or not to produce additional workers, I just Ctrl - Click a worker or box them. When the selection-tab shows around 20-24 drones (per base) I usually stop production (that's about 24-28 workers total, since 4 are usually in gas if both geysers are taken).
In the late game worker production is usually really low. Rather transfer workers from partially or fully mined bases instead of building new ones. Just don't forget to replace workers that died from harassment or drones that were used to build stuff when playing Zerg.