My previous roommate had a groaty ass boyfriend who brought bedbugs into our apartment. I have had a light infestation ever since April.
I've kept it under control by changing the sheets every couple of days, washing them in hot water, and putting diatamacious earth (sp) in the folds of the mattress, box springs and bed frame.
I rarely get bites even though I find a dead bug every other week.
The reality of it is, this being a college town with many international students, the chance of getting bedbugs increases greatly. Many cultures live with bedbugs and are not bothered by them. When they move to the US, much of their luggage is not thoroughly inspected and bedbugs make it into the border.
If you live in rental property wash your sheets very often, don't keep clothes on the floor, and inspect your furniture regularly.