I began Reta in mid March, added KLOW in mid April, then started CJC/Ipa in mid May. Roughly a month between each one. I've kept the same Reta dose since mid April.
I've only been using Reta for a few weeks and am still raising my dose toward the target. So far it's gone smoothly, with six pounds lost and just a bit of stomach upset on day one. I'm close to satisfied with how fast I feel full and probably need another half to one milligram per week. Looking into other peptides such as GHK-Cu, MOTS-c, and MT-2, the usual advice is to space them out so you can tell what each one does on its own, though the right interval varies. I'm curious what general waiting period people follow before adding the next item. My own thought is at least until my Reta dose has settled.