If this is your first episode of depression
and you are still on antidepressants, the evidence is that you should continue on the thereputic dose for another six months and then stop. This helps to reduce any relapse of the symptoms.
If this was a severe epsiode with risk to your life/others/
If you have strong family hsitory of depression like in your parents/brothers/sisters
If you have ongoing stressors which have caused this depression in the first place
the evidence is that you might have to continue the drugs for longer than 6 months
If this has been a recurrent episode then you might be lookign at long term to help you not have any future episodes.
If you are having any symptoms left over (residual symptoms) then you msut be contacting your treating doctor to see what can be done with that.
The most important things to learn from any episode of these kinds of problems where there is a chance of recurrence is how to prevent future ones/get help fast enough once they re-occur
apart from medicines
you need to be aware of what triggers caused depression, if any, this time and keep a look out for lowering of mood the next time you are going through those triggers, if it is not possible to eliminate them at all.
For ex, drinking alcohol to excess when causes depression should point to the flag which says "DON'T DRINK ALCOHOL" ETC
Hope this helps