While some pests need frequent treatments because they occur rapidly, other pests do not appear quite as often. 

There are several factors that determine the duration of your pest control measure. They include:

• The kind of pest
• Your environment(desert, close to sea, mountains, etc)
• The severity of the infestation
• The quality of the pest control measures used
• The chemical used
• Skills, knowledge and efficiency of Exterminator

Some advanced pest control products are safe for both pets and humans. So, you basically do not have to leave your home. Though, most exterminators would advise you to wait for a few minutes to allow the treated surfaces to dry. 

However, pregnant women and people with certain medical conditions like asthma should be very cautious and follow the advice of the professional. Generally, it is always safer to stay out of your house for some hours after pest control.

• Dispose of any food left outside or uncovered
• Do not be in a hurry to clean up
• Repair any leaks or holes
• Protect yourself with gloves when dealing with the sprayed surfaces.
• Watch out for dead pests and remove them to avoid arrival of new pests