Curbs told the Mirror: "It's the life we're in at the moment. Unless you get results and success quickly then you don't get the same time anymore.
"When you get to a high profile club everything you do is going to be looked at - body language, the way you walk onto the pitch, the way you dress, every last detail.
"Being a manager is getting tougher.
"That honeymoon period has gone. You even look at someone like Dave Jones at Cardiff who was under pressure and then he turned it around.
"I think you get applauded over the top when you win, then you get over castigated when you lose. You have to take it with a pinch of salt.
"I've never been under too much pressure as a manager, apart from maybe when I was first at Charlton when I wanted to do things and change things.
"Even Sir Alex had a period where it wasn't going so well, but United showed the foresight to stick with it and I don't know if that is there any more. I managed my last game at Charlton at Old Trafford and I had done 15 years and Alex had done 20 years. I said to him the days of the two managers doing 35 years between them have gone."