Some big questions in here methinks...I did what you are proposing. i.e. moved into consulting from mfg/eng in my mid 30's so I'll try to give you the benefit of my experience to date.First of all, I have never regretted the move away from industry which was somewhat forced on me by a lack of future career options but to answer your points:1) Most if not all people from industry realise very quickly that once they have made the move they will either like it or leave it. Be clear in your mind why you are doing this because you are about to step onto a steep learning curve which is often unsettling to people who are used to well organised, well regulated industry life. If you can make that switch then you'll be fine and most I have met do indeed survive and prosper.2) The key difference is the need for you to be self motivated. I find it easier to think of myself as self employed and look for validation rather than permission. I am not advocating anarchy just an accpetance that you have to get on with it and find a way to succeed.3) Travel, be self managed, be prepared to contribute your weight, learn a lot of new stuff and attitudes quickly.4) Bit of both, many consultants are quite young in my experience and look to people with more experience to steady the ship. Having said that they are almost always talented and pretty ambitious themselves. I have found clients tend to react better to more mature consultants having said that I have also seen some excellent work done by my younger peers. I don't belive that chronological age is the key, I would suggest you need to understand that many people will have better skills than you for a while as they are more experienced.5) Not really, how much job security have you really got right now??Good luck and make sure you join a good organisation, that may be more than half the battle. Do recognise that it can be done but you are starting on a learning curve.