Tool man

PDA: He could store notes and dates that he needs to remember, thus eliminating the need to carry countless diaries, along with a rechargable battery (depending on the PDA model) it would save money needed to buy diaries.

GPS: will be incredibly useful, as it will get rid of the "large road atlas and numerous A - Z's" he has in his car, compacting it into a small box mounted on his dashboard. Not only that, but it will automatically plan the route for him, freeing up potientally countless hours sat at home planning out routes to his destination. Depending on the make, it could also provide regular traffic updates, allowing him to avoid the traffic jams. It would however be wise to keep a map in the back just in case of a GPS malfunction.

Laptop: The main function he could use this for is for all the administrative work, also, due to the portability, it can allow him to do some in his van during spare time between clients. It can also be used to backup files for his PDA.

Mobile: As long as he has a hands free kit, it will allow him to call his customers, giving them updates such as whether he will be late due to traffic. It will also allow him to call the emergency services, without him having to run to a pay phone, as long as he isn't in a spot where he can't get any reception. Due to this reason it would also be wise to keep some change on him for a pay phone.

Internet: Look up background information on his clients, along with using it to build his own website, bringing in more business due to the increase in advertisement.

The disadvantages of this however, is the electricity he uses will increase quite a bit, along with the fact he will have to manage certain hardware so as to avoid viruses (e.g PDA, laptop). It is also harder to fix a laptop than it is to recover a torn page.