come on guys this is not a pissing match.so you can switch up the test and youll be ok.but deca you can run for a period of time.but if you run deca by itself will you need test with that as your running deca?
No need to switch test bro, just pick one and go with it. You can however switch to prop at the end of your cycle since it is a short acting ester which only remains active 24-48 hrs. Doing this will allow the longer esters in the test you've used through the bulk of your cycle to clear out, and allow for a smooth transition into your PCT. Switching to prop at the end is also beneficial if you're preparing for comp, because it tends to bloat you less when used for a short period as compared to the longer-ester based test.
As far as choosing what test to use, it's not all that crucial. You can go with test-e or cyp and expect almost an identical result since they are identical in makeup, injecting 1x per wk is usually sufficient. As for myself, I prefer sust as my base for all my cycles, it tends to bloat you less, it also seems to provide a bit of an added pop with the prop mixed in it, and the other 3 test in the compound which are mixed on a basis of time release seem for me at least to provide a much smoother ride over-all. A lot of people claim that it is too difficult to keep blood/test levels at a comfortable place when using sust because of the various esters, but this is false. A lot of people also claim that because of the long acting esters it should only be injected every 7-10 days, also false. If you wish to keep blood/test levels stable and if you want to take advantage of the prop it should be injected 3x wk...myself, I prefer 4x wk, it's just a lot smoother.
Duration of test use depends on first and foremost your level of experience. A novice should never run very long cycles because they have no idea how their body is going to react. That doesn't mean you should run it 4-6wks, not at all, you have to allow the test time to become active in your body, and short cycles do not allow for this.
Yes, deca should be run with test, and should be discontinued at least 2wks before your cycle ends.