Plastic, like most consumable packaging, has for a long time been a through-put design. Resources would be used to make bottles, which would be consumed and eventually thrown away. In this model, resources move in one direction, from production to consumption.
Thankfully, in the 21st century, we have recycling which promises to loop the resources back into the production cycle and divert them from becoming waste. In an ideal system, resources would never reach landfills and instead be caught in a regenerative cycle.
Unfortunately, our current recycling system is just not that efficent and we are left with some material being recycled back, while some is still diverted to landfills. While every recycling system is different, in general PET plastic bottles could be reused up to 7 times. This is roughly 85% efficent.
However, not all plastic is created equal. There are 7 types of plastic that can be recycles, though most places will only deal with PET, HDPE and PP. The technology exists to recycle the other 4 types but depending on the supply and demand, they might not be available in your municipality.
Try clicking on one off the plastic types and scroll down to see where the product ends up. You can add and remove proccesses to see how it effects how much keeps in the system. Maybe research what your munipality offers and get an idea for where your plastic really ends up.