This page documents my main approach for OSCP preparation, meaning 2 to 6 months before registering for PWK. The three-pronged approach would be: Coding/Scripting + Learning Theory + Machines Practice
These sites with machines or challenges are listed from what an absolute beginner should start with, to the end, right before signing up for the PWK labs. An estimated total of 300 to 400 hours cracking machines along this route is a good target before attempting PWK labs, from what I've gathered from other cybersec community contributors like TCM, TJnull and others.
Over the wire (Linux system)
TryHackme (Beginner)
Vulnhub (Huge numbers of machines with walkthroughs)
root-me.org
HackTheBox + IppSec videos + Walkthroughs (Definitely not easy, even for those "easy" difficulties)
TJNulls HTB list to complete (Absolute essential to go through the boxes in this list)
PWK Proving Grounds (Practice and Play)
OSCP PWK Labs 90 days (Final)
Tackling the OSCP PWK Course + Labs
Do entire PDF (800pages) + exercises (2 weeks to 1 month)