From my wonderful friend Agata Zasada, Human Relations dynamo:

So many times managers forget the journey it took to hire an employee, from last year’s budgeting, the job descriptions, interviewing and making a final decision. Many things can change over the course of time, so it’s important to realign your new hires purpose, expectations, measures of success and what the first 90 days should look like (or whatever number of days). Here are some things to consider and get you started.