In my experience, either you feel it (like AMASH does), or you don’t. If you don’t, you might determine a mandatory listening time for yourself. Generally, 1 month is a reasonable bet.
If you are anxious to move on beyond the first stage because you feel that there’s nothing left to fix there, then you might go for two weeks for the first stage. If anything is going to pop up, it will likely be evident within those two weeks. And if nothing pops up, at least there’s been some prep work even if you didn’t notice it.
If this is your first SubClub subliminal, you’re giving your subconscious the opportunity to get used to the style of scripting and patterning that SubClub uses in their products. As a hypnotist, you must have experienced clients can go deeper once they get used to their hypnotist and his/her style. Same goes for subliminals.
Keep in mind that stages 2 and 3 are repeated in stage 4, but stage 1 isn’t. Once you move on from it, you’ll miss out on everything it could have offered. So don’t be too quick to write it off as unnecessary.