You should meet with your personal trainer 1 to 3 times per week, depending on your current fitness level and experience, short-term and long-term goals, and how often you're able to train solo during the week. Most trainers recommend beginning with 2 to 3 sessions per week for at least six weeks to establish a routine.
If you're on a budget and can only meet with your personal trainer once per week, you'll need to train on your own at least one to three times per week to make progress toward your fitness goals.
Consider seeing your personal trainer up to 4 times per week to work on short-term goals, like dropping a dress size before a wedding or training for a sports competition.