The First SpaceX Falcon 9 Block 5 should launch in April and each could be reused 10 to 100 times

The current SpaceX Falcon 9 boosters that have been recovered were only designed to be reused 2-3 times but the new SpaceX Falcon 9 block 5 are expected to last for ten reuses.
 
SpaceX has about 6 recovered boosters which will be reused. Most will be reused and not recovered in the next several launches.
 
SpaceX ic counting on Block 5 to succeed with increased reusability and for faster relaunching. If any design or manufacturing flaws are discovered in the first several Block 5 Falcon 9s, or if Block 5 is less reusable than SpaceX then SpaceX could have delays in its launch schedule.
 
The first Block 5 Falcon 9 first stage is on the test stand at their McGregor, Texas test facility.
 
The maiden flight is planned for April 2018, with the Bangabandhu-1 satellite. 
 
SpaceX Block 5 improvements:
 
Alterations are focused on increasing the speed of production and efficiency of re-usability. SpaceX aims to fly each Block 5 booster ten times with only inspections in between, and up to 100 times with refurbishment
 
For increased payload:

* 7–8% more thrust by uprating the engines;
* an improved flight control system for an optimized angle of attack on the descent, lowering landing fuel requirements.
 
For reusability endurance:

* a reusable heat shield protecting the engines and plumbing at the base of the rocket;
* more temperature-resistant titanium casted grid fins;
* a thermal protection coating on the first stage to limit reentry heating damage;
* Redesigned and requalified valves for higher levels and much longer duration.
 
For rapid reusability:

* a set of black retractable landing legs for rapid recovery and shipping.
 
Block 5 is planned to launch astronauts for the first time in late 2018. NASA requires seven flights before the vehicle can be certified for human spaceflight.