1) Drive's dosage recommendation, like other AN products, is weight dependent. Someone weighing up to 150 lbs would use a bottle for almost two months (at 2 caps per day). If you weigh between 150 lbs and 200 lbs, one bottle would last you about 27.5 days (at 4 caps per day). Above that weight, you might need six caps per day. Do not forget though, that these are average recommendations. Considering that we are all different, it would not be a surprise to find someone weighing 250 lbs that has his "sweet spot" at four capsules per day, or someone weighing 150 lbs that needs 4 capsules daily.
2) You may decide to take your Drive once a day, so that instead of doing 2 x 2, you might end up with 1 x 3. This might be useful on work-out days. Overall results would be the same, regardless of whether you do a single or a split dose. One advantage is that you might stretch your bottle longer. You might want to see if this will work for you. Some other have found it useful.
3) The general recommendation is to load Drive at 6 capsules per day for about one week to ten days so as to elevate cellular concentrations of the active compounds. Afterwards, you should revert to the dosage recommendation for your weight category. Some people ended up taking 6 caps even after the loading period, seeing this as their "sweet spot". Nothing says your "sweet spot" cannot be different.
4) Finally, if you take Drive and RPM together, you tend to "save" on the dosages of one or both of them. This way, the bottles last longer than they would, if taken solo.