Absolutely. Be it ten months, ten years, or thirty years, individuals with OCD can always benefit from treatment and get better.
As long as they are willing to challenge themselves and to listen to the advice of their treatment providers (such as to do exposures and to take their medications as prescribed), there is no reason that they cannot be successfully treated.
The biggest deterrent to getting better would be to believe that it is too late for therapy to be of any assistance. Without therapy it may be very difficult for people to get better on their own, especially if they have had OCD for so long.
That is why it is important for people to find specialized treatment providers who will be able to assist in their recovery.