Agree with 2 hours.
For T1:
10min train platform up to check-in.
up to ~25min check-in.
5~25min security then passport
up to ~10min to gate
So I'd say minimum 80min before departure. Longer if you want to make certain you have overhead bin or if you don't want to rush. 2hr is comfortable and allows a bit of time for last-minute shopping.