Good question, and this is a question that we have discussed here on this forum many times. The general 'consensusthink' is that once a day is good for maintenance (i.e. would probably keep what you got, and maybe thicken up the existing hairshafts), but if you want your best chances at actual regrowth (more scalp coverage) you'd better go to twice a day, and be religious at sticking to it. However, this is just the 'rule of thumb' and in reality if anyone actually gives you a definite YES or NO answer to this they are lying. The truth is that despite the 'rule of thumb' that might be anecdotally accepted, in reality one cannot know how once a day minoxidil versus twice a day application might affect you. You might grow huge hair, or, it might do nothing, or maybe something in between. Every individual person responds differently to it.
As for the 'minoxidil looks terrible in my hair' point, I completely agree. Do you have dark hair?... because I think it is a dark hair thing, but, minoxidil tends to leave hair greasy at first, and as it dries tends to leave a white film on some people's hair. It did for me. So, I use a different application technique that I learned here on this message board from a fellow contributor (Cassin). Basically we wash, dry, and style our hair FIRST. Then when the hairspray dries, or whatever, and the hair is relatively dry we take the dropper and fill it with minoxidil. Then, carefully wipe the sides of the dropper so there is no wetness on it. Then, we carefully 'poke' the dropper through the styled hair until it hits scalp. Then let a droplet go. Continue to dot the affected area of the hair until your 1ml of minoxidil is depleted. If you are careful, and make sure to wipe the sides of the dropper dry, and you allow time for your styled hair to dry first, you can do this without getting very much in your hair at all, and without ripping up your hairstyle. As we do NOT rub it in with the fingers (which I think is better anyway because less minoxidil on the hands and hair means more on the scalp), for a few minutes you will have droplets of the sh*t just hanging onto hair roots. So, after applying, you have to sit still for a few minutes to allow the minoxidil to set a bit without running. But, it is well worth it to me. This technique takes about 10 minutes tops, and after the 10 minutes although the minoxidil is not completely dry, the wetness on the scalp is hidden by the dry hair above it. So, I can get into my car and by the time I get to work I am fine and dandy. Morning minoxidil applied, no grease or residue in my dry and perfectly styled hair, and I'm ready to hit the ground running after a final check that there are no remaining drip marks near the hairline area.