In our teaching lab (general microbiology), we stress handwashing,
disinfection of all counter surfaces before and after all laboratories,
aseptic transfer technique, and ask that the students wear either lab
coats or long-sleeve, fitted shirts to cut down on the chance of skin
contact with spills or biological stains (the more likely of the two).
Gloves are optional, but recommended. When I was a student, these
practices were also taught, and I personally believe them to be solid. As
you have stated, personal preference does enter often, but I really think
that by stressing the basics of cleanliness and how contagion is spread,
we can help reduce poor habits caused by lack of information and
inattention to detail.
Dr. Karl J. Roberts