I would think a lot depends on the other person involved in an affair. For example husband is having an affair w/ a stay-at-home wife. He can claim he's @ a business luncheon or out of the office for meetings & no one would be the wiser as long as it wasn't obvious like doing it every day. Or the Other Woman could work in his office & they could have "nooners" w/o too much suspicion.
The same could apply to a woman in reverse if she's in a corporate job. If she's a stay-at-home it, could be any time between when the husband leaves for work & when he comes home. She has to go to his apartment if he's single or divorced, or go to a motel/hotel or she runs the risk of a husband coming home early or nosy neighbors.
Really, it depends in each situation who is better @ hiding the "evidence"--no cell calls, e-mails, text messages, no receipts, no guilty pleasure in constantly mentioning the lover's name, no unexplained trips out-of-town, meeting in motels/hotels where friends/family wouldn't see you w/ the lover or going in/out, no new clothes & certainly no new sexy lingerie, always showering after the tryst to rid yourself of perfume/aftershave, no new fragrances--esp. cologne or aftershave for the guy who never previously wore it, making sure no slip-ups & calling the spouse by the lover's name.