One of the issues is that all esters peak in around 24 hrs, and start to decline. With long esters the decline is much more gradual, but they still peak pretty rapidly and start to fall, prop just falls more dramatically after its initial "spike". Even though the half life of Test E/Cyp is on paper 7-10+days, most would agree twice a week dosing is better for stable blood levels. Regardless of how much gear you inject also, if you use the same frequency and dosing for a while your levels will eventually build up to a maximum amount they will not just continue going up forever, even though you may be injecting more frequently than the half life. So there is no real detriment (besides extra pinning) to doing 2-3x a week with a long ester, or blend like sust, and it will prevent the test prop from leaving your system and blood levels dropping between injections. I also wouldn't say its a waste of gear to do it more often, I doubt most guys here use enough gear to truly "max out" their ability to respond to it.
On the flipside, yes you can use test E/sust what have you once a week, you will get a larger peak in the beginning and lower levels at the end of the week than more frequent dosing. Your results however in terms of body composition etc. will probably be about the same, you may have more anabolic activity in the beginning of the week and less at the end, but it will probably roughly equal out to what you would've gotten in that week with steady blood levels. Your personal experience of the cycle as far as mood, libido, side effects etc. may be affected though and if you don't mind an extra injection or two a week it would only be a good idea IMHO 🙂
Edit: I've been experimenting with test undecanoate for cruising for a little while now. I've found I can do injections as far apart as 2-3 weeks and still be ok, though I tend to go around 1.5-2 weeks. I "frontloaded" a pretty healthy amount recently before a six week vacation, and still had good libido etc. by the end of the six weeks. One study I read on undecanoate/nebido said that injecting every six weeks caused blood levels to rise each time so there was concern even that was too frequent, but IMO smaller doses 3 weeks apart would achieve more stable levels and a better patient experience even if it isn't necessary to keep the patient above "reference range" at the end of six weeks.
