Can a house have only a mild infestation of bed bugs?

The important point to understand is it is not "YOU" that has bedbugs but a bed or sleeping place may have them which you use. It is possible in the very earliest stage of an infestation of a particular bed for there to be just one or two bedbugs that have set up their base near there perhaps for several weeks or longer. For example in a hotel bed used by five different people on five different nights booked in for bed and breakfast, every one of those five will have bedbugs, but only during the night they are sleeping in that hotel bed. This may well be before there is any major infestation which the hotel management only then may get made aware of. Also in a bed at your home you may just have one or two bedbugs feeding off whoever used that bed for a prolonged period, before a major infestation happens,. then you so become aware of a need to deal with a bedbug problem which you may not have originally been aware of. A serious bed infestation only starts happening when more and more eggs laid by bedbugs in or near that bed start hatching, and then when the nymphs become adult bedbugs they start laying more eggs, so more and more new bedbugs get born and the user of that bed finds them-self covered all over with red bite marks.