The bedbugs hide in crevices (any type of crack will do) and in fabrics. Removal of electrical covers (switch and outlet plates) prior to extermnation is recommended. Removal AND disposal of all fabrics (carpet, carpet pad, curtains, clothing, furniture, etc.) is also going to be recommended. If there is any warranty from the exterminator, it will probably require that those recommended things be performed.
Three treatments is the norm for bedbugs. Don't be surprised if both dust and fogger are used.
In a SFH, landlord should be certain to have in the lease that extermination is the tenant's obligation; in a multi-unit, it's almost always going to be the landlord's job.
If you don't want a tenant to stay on at the end of lease, be sure to provide all notices as stipulated in the lease, and be sure to comply with all landlord tenant law. If tenant does not voluntarily leave, you then have to do an eviction. Your tenant may bring up code violations (failure to exterminate), and that can derail the eviction process. Usually, in order to successfully evict, you will have to be code compliant or prove completely (without a doubt) that any code violation was caused / inflicted by the tenant. Could be tough to do with the matter of extermination; in row homes, bugs will move from house to house.
There are many reports of people acquiring the bedbugs while traveling; the hotel stay, with luggage and clothing, has been found to allow for the bedbug to "stowaway" and emerge at the travelers home.