As a general guideline, while all negative items will impact your score for the full time (7 years, typically) that they're present on your CR, the impact will lessen by 1/3 for majors and 2/3 for minors, possibly on or about the 2 year mark. So, to assign numbers to it for the sake of discussion, let's say that a brand new baddie drops one's score 90 points. If it's a major, after 2 years perhaps 30 of those points are regained, where the remaining 60 won't come back until the item falls off the CR. If it's a minor, after 2 years perhaps 60 of those points are regained, where the remaining 30 won't come back until the item falls off the CR. It's also important to understand that these numbers I'm speaking of above assume the presence of only 1 negative item. If you're talking multiples, it's a different discussion.
From what I've seen, major or minor, 1 year of time as you asked in your post is not significant in seeing score start to rebound, but rather 2 years seems to be a commonly reported threshold.
i posted this in the other thread about scorecards.
here is what they're looking at in a dirty card. most important to least:
severity of worst delinquincy ever
months since last 30+ days past due
# of inqs in last 12mo
length of credit history
for a dirty file, they punish your payment history, which is the most important part of your score.
here's an example of how they do that.
# of months since most recent derog?
no derog = 75
0-5mo = 10
6-11mo = 15
12-23mo = 25
24+mo = 55
(these aren't the final fico points, they're temp points for adding up your scorecard)
this gives an idea about the timeframe for it to affect the score less.