Check if your course load is manageable.
The standard planning assumption is two hours of independent study for every credit hour, so a fifteen-credit semester is a forty-five hour academic week once contact time is included. Adding paid work and comparing against the hours you can genuinely commit reveals whether the enrolment is feasible. A slack figure near zero is the warning sign, because deadlines cluster rather than spreading evenly.
Academic load
Academic hours = credit hours + credit hours x study hours per credit
Feasibility
Slack = available hours - (academic hours + paid work hours)
It is the standard planning figure and works well as an average, but it varies by subject and level. Quantitative and lab-based courses often demand three, while some lecture courses need less.
Research on undergraduate outcomes tends to find effects becoming negative beyond roughly fifteen to twenty hours a week during term, largely because study time is what gets displaced.