Antiques, even new furniture can bring in new mold to your home. You will have to be very diligent going forward in how your home can be exposed. We recommend purchasing a spray bottle of MoldStain T-Klear to clean items BEFORE you bring them in your home.
Having your windows open in spring can also let in mold. Place humidity meters in your home to monitor each month. We suggest that if humidity is nearing 55% that you watch more diligently and are conscious to not let it reach 60%.
Regarding your garage, your house is positively pressured so when you open the door from your house to your garage air should flow out from your home not in. Treating a garage that is not climate controlled or whose door is opened often will be hard to maintain humidity control.
Nothing guarantees mold will not return. You will have to remain diligent and repair any moisture intrusions within 48 hours.
Even new construction materials (i.e., cabinets can contain mold). Have you ever purchased something from a garage sale or thrift shop? Consider cleaning those items by wiping down prior to putting in your car or home. If having work done to you home, have your contractor use containment in that area so if they open up a wall or tear out flooring, the debris and possible spores remain in that area. Make sure debris is placed in plastic bags or wrapped prior to moving through home to dispose. Treat area with fog treatment prior to containment area being disabled. Spend $10 to get humidity meters and place in several areas in your home to monitor humidty and don’t let humidity get over 60%. Change furnace filters often. Consider adding a dehumidifier on your HVAC unit. Repair water leaks within 48 hours.