Regardless of your Dbol dosage, four to six weeks of use is about all anyone will ever need; some may extend to eight weeks total, but this should be rare and is normally not recommended. The reason for such short-term use once again revolves around this steroid's strong hepatotoxic nature, and if you ignore the recommended time frames you will put your liver at risk. Of course, as seen from the Dbol only cycle link, your total cycle should extend past this point of use or you will risk losing all your gains. A solid plan is an injectable or two with your Dianabol for six weeks, and then continuing the two injectable steroids for another twelve weeks.
However, if you are only using Dbol as a supplement (. only using it for a temporary boost for training or recuperation), then you need to experiment to determine whether pre or post training is best for you. Pre-training is still good for the rationale indicated above, but when I did Dbol only (used like a supplement which meant ONLY on training days) I got the most benefit taking the Dbol AFTER training. Using Dbol this way really really cut down on my recuperation time. For me, comparing those training days when I didn't take anything pre or post to when taking the Dbol post was a significant difference. When using Dbol as a supplement in this way, I only used the Dbol on those training days where the volume/intensity was going to be very high.