In English, people often use this expression when they are not sure of the exact amount of time. For example, when the mechanic says your car will be fixed in "a couple of hours", he means it may be 2, 3 or more hours. He is giving you an estimated time frame but he doesn't want to be committed. If the nurse in the hospital says the doctor will see you in "a couple of minutes", she means 2, 3 or more minutes. She is giving an educated guess but doesn't want to be specific. A relative, visiting you for "a couple of weeks", might stay for 2 or 3 weeks but not a month. You might describe their visit this way because you are not sure when they are leaving. When people say "a couple of minutes (hours) (days)" it can be frustrating. You can respond by saying, "can you be more specific". Hope this helps

Usually 2 or 3, but maybe 1-5? It's a way to give a vague idea, not be specific. 'You will have to wait a couple of weeks to get your test results'. 'Once you have lived there a couple of months, your language will start to improve'. 'Can you wait a couple of minutes? I need to make a call'.