HOW long do you give a player to prove he is worth a place in your team?
That depends on many things including age, experience and what adaptations they have had to make as a result of where they have come to you from.
Lassad Nouioui has now been at Celtic for half a season, having arrived at the very end of the summer transfer window after having run down his contract at Deportivo La Coruna.
He is a 26-year-old striker who has represented his country, Tunisia, and his record in Spain was such that Celtic were not the only club chasing him.
But, Lassad has yet to really convince me he is worth a starting position in Neil Lennon's side.
The manager has said he has been unfortunate with a few injuries which have impeded his progress.
And, I can see what he really needs is an extended run in the side – preferably through the centre – to get him to where he needs to be in terms of sharpness.
There have been a few glimpses of his ability and intelligence, like the part he played in the set up for the first goal against Dundee United last midweek and the way he finished against Hearts the game before.
But, too often he does not get himself involved enough, and he was once again substituted in Sunday's cup semi-final against St Mirren.
Neil seems to like him, sees him every day in training, and continues to involve him hoping that his faith will be repaid.
But, to the rest of us, the jury is still out.