On one hand, you need to be able to ID repeat customers.  A log book or journal is much more dangerous, in LE hands.  I'd rather you deleted all the address book but would understand if you chose to keep first names & numbers.
On the other hand, I have my hobby phone & delete everything before I leave the location.  If it falls into the wrong hands be it LE or a spouce...  at least I did not make it easy.   The annoyance is I must go to your web sire to get your phone to make the calls because theyt are deleted.  

Probably texts & emails are the most dangerous.  Delete at once since likely your laptop will be a your locatrion.  

Don't keep records that are potentially incriminating...  just don't.   In most jurisdictions this is a petty crime.  LE may gather any info that is laying arround but LE will not go to great lengths & expend a lot of energy unless someone is high profile or a more serious crime has been committed.  
H