Any contractor or subcontractor who works on your house should be bonded, licensed, and insured properly according to state and local standards. Insurance can help protect you if your home gets damaged during construction or workers are hurt on site, while hiring a bonded contractor can help protect you if the contractor fails to pay workers, doesn't pay for permits, or doesn't finish the work. Here's more on how to do your research.
With this article being close to 2 years old, I can easily say it is WAAAAYYYY out of date and couldn’t be farther from current outcomes. While some of the occurrences with the difficulty in getting responses from contractors might still be the same, the dollar figures are multiples off! My wife and I have been researching a modest renovation on our master bath (mid70’s colonial MB that was updated once before) and have reached out to multiple contractors over that timeframe. Each time, our revelation into the exhorbitant costs are proof enough we’re not asking either the right questions or the right contractors. The dissapointment in hearing the $30k minimum and 45$k midpoint (again...midpoint) for our studs to simple remodel are enough to send us into the nether-regions of misunderstanding and annoyance and the same time.
Between the two options, pick up one tile design that suits your necessity and budget. Remember to put forward safety for your children in this point. In case your budget is limited, you can partially change the tile. Determine which part of the bathroom that needs new, safer tiles. This will definitely save more money compared to overall tile changing.