I retired in 2000 after 34 years in teaching and enjoyed the job immensely. It proved very satisfying as a career, helped, I feel, by my working in Further Education with well motivated students of all ages(over 15). I'm not so sure that it would be as enjoyable nowadays. I'm told that many students are less well motivated and administrative/business structuring and financial decision making take precedence over academic need. With a Science Degree, however, your son can afford to be selective about the type of institution in which he wants to work. If I were starting again I would probably head for a School witha strong religious affiliation, where my impression is that attendance by students, application to work and study, and general behaviour issues are positively addressed.