This is a question that one must answer on a DAILY basis.
It is, l’havdil, like paying taxes.
If one has a business, earns good money, but doesn’t pay his taxes the whole year, when April 15th comes around, he’s in BIG trouble. If he pays his quarterly taxes throughout the year, he should be in pretty good shape.
Likewise, if one makes a cheshbon ha’nefesh on a daily basis, an assessment of what he’s been doing, does teshuva for what he needs to do teshuva for, i.e. cleans his slate, so to speak, then when Yom Kippur comes around, he should be in reasonably, manageably, decent shape. If not…