The old professional adage about practice is "if you skip one day, you notice, if you skip two days, your wife/GF notices, if you skip three days, everybody notices."
And old acquaintance of mine, who is a highly successful musician asks "How often do you practice?" when other people come up to him and says: "Hey, I'm a musician too." If the answer is not "Everyday" he just kinda blows them off.
I do the same deal with people who say they are writers. I ask, how many pages they write a day, or at least, how many hours do you sit there and try to write, and if they are not trying to write every day, they are not trying very hard to be a writer.