SpaceX just used 39A for CRS-10. Do they have any plans to repair SLC-40 from the September anomaly? The Boca Chica launch center should be ready in 2018, so will they solely use 39A and Boca Chica?
On the prelaunch press conference about LC-39A Gwynne Shotwell (SpaceX COO) said that they plan on repairing the SLC-40 pad now, hoping to finish it in summer.
Preparations for that [Falcon Heavy debut] launch will begin once repairs to SLC-40 are completed, which Shotwell said should be in June, allowing Falcon 9 launches to resume there.
IIRC June in the article is not exact, Summer was used without specifying a month.
SpaceX started with a pad at Vandenberg for the Falcon 1, but got kicked out of it because they were considered a risk for a Delta pad nearby.
Then they opened up at Kwajjelin Atoll. They launched the 5 Falcon 1 launch attempts from there
They opened SLC-40 at the CCAFS and launched most of their launches (minus 3 at Vandenberg, and one at LC-39A as of this writing) from there. The AMOS-6 fueling incident did sufficient damage that they switched focus to the LC-39A to buy time to fix LC-40.
The plan going forward is to launch Polar missions from Vandenberg, Falcon 9 and Falcon Heavy.
Initially NASA, government, and Manned flights will launch from LC-39A. This is Falcon 9 and Falcon Heavy capable.
LC-40 will remain for Falcon 9 flights. (The plan for Falcon Heavy launches from LC-40 essentially means building an entire second pad, on the edge of the current pad and seems unlikely to happen).
Boca Chica, Texas can only launch to a narrow set of orbits due to landmasses underneath the flight path.
So LC-40 will be rebuilt and used. LC-39A will be used. SLC-4E will be used for polar missions. Boca Chica will be used once opened.
SpaceX clearly believes they have sufficient demand for all these launch pads.