Rationalize the biggest purchase of a person's life. This is the maxim of a personal shopper real estate, a fairly unknown professional profile that has a single objective: to defend the interests of the buyer. One of them, Jordi Clotet, co-founder of Nexitum and author of The 7 doors to buying your home and getting it right, written after having visited more than 15,000 apartments throughout his career and having participated in 6,000 sales. Here's some of the advice he gives.