If you're taking aspirin because you have a history of heart attacks and even strokes or you want to prevent a heart attack or stroke then taking the aspirin at night is the best thing to do.
Studies have shown that the aspirin is most effective when you take it at night but it's still pretty effective during the day as well.
My dad has heart disease and has had a heart attack before and his doctor advised him to take the aspirin at night before bed because the doctor said it would be the most effective then.
If you have no risk of heart disease or strokes and are a younger person in good shape then I would not recommend taking a daily or nightly aspirin unless you need too.
Taking aspirin too much can cause kidney issues and other health problems but it's okay to take the aspirin when needed or if you have the risk of heart disease or strokes then taking it daily or nightly is okay.