It is probably impossible to completely guard yourself against getting bed bugs, but with some consideration, the risk can be significantly reduced.
If you have slept in a place where you have been bitten or you simply suspect bed bugs have been there, it is a good idea not to bring your luggage directly into the house. Find an appropriate place where it can be in “quarantine” and check the content before it is brought inside. Clothes may be put directly into the washing machine, or a week or so in the freezer. If the suitcase or backpack has any suspicious cavities it can be sprayed with an insecticide.
Used furniture poses a risk. The beautiful painting from the flea market or the bedside table from the container should be thoroughly checked before putting it in use.
There has been no experience with standard mosquito repellents being effectively preventive against bed bug bites.