I don't leave home without it. It is compact and useful. The tool every homeowner and renovator should buy: a laser measurer. You may never need an old school measuring tape again.
It comes in handy all the time. I keep one with me when I tour homes with home buyers and give them as gifts to my real estate clients.
When it's time to renovate, one of the first things you'll need to do is get accurate measurements. While you'll need detailed floor plans if you're doing an extensive renovation (in which case I recommend a progessional), a laser measurer will help you get accurate more precise than tradition tape. This tool will be especially helpful if you love to DIY.
I carry a Bosch Laser Measuring tool, which is easy to measure large rooms. They come at various price points depending on the capability you're looking for.
This one can calculate room area and volume. Area will be especially helpful when you're looking to estimate material costs for items like flooring. Make sure the model you select can measure distances in your home sufficiently.
There are lots of options available, so find one to suit your needs here: