I would never wear a windowpane suit to a job interview. You are best to stick with more conservative suits with no pattern or a very discreet pattern such as a faint pinstripe.
I would not wear a windowpane suit when meeting with a prospective or new client that I am meeting for the first time. On these occasions I would stick to more conservative and traditional suiting choices.
When choosing a very obvious windowpane suit pattern, I think you are best to then choose a shirt and tie that has no patterns or just very discreet patterns. This will allow the windowpane to be the dominant pattern without clashing with other patterns.
If wearing a windowpane suit in a corporate setting, I would choose a more discreet windowpane pattern.
It is then more acceptable to wear a more obvious windowpane suit pattern for more social events such as attending the horse races, an engagement party or wedding, an up scale social event or date in which a suit is required.
Don’t wear a windowpane suit to a funeral. Stick to more traditional and low key suits that ideally has no pattern or a very discreet pattern.