No offense to sbdman, but that statement is inaccurate. It’s Bro science. From both a chemical basis and my own personal experience/testing, this isn’t necessary.
The theory behind overlapping the two esters is allowing the Test E to build up. However, your receptors are already saturated with test. You are not needing 2 weeks for the ester to be cleaved off. The second you inject, the ester is already being broken down and you have test beginning to fill receptors. But they’re already filled. You may be ok carrying on with Test P for 3-4 days max, but if you go much past that, your levels will be spiked. Which we want stable levels.
In my own experience with testing when I ran Test P overlapped, my levels went through the roof after day 4. Now on another experiment, I stopped Test P immediately and started Test Cyp. I never once saw a dip in total test. I tested every 3 days. The chemistry supports the blood work as well. I know a lot like to read the forums and just follow the advice on them. I actually have an academic background in bio-Chem. So I like to do my own research and testing. Not that some of the bro science stuff is wrong.