It's usually nice to advice as long as you don't insist you're right and as long as the person you advice doesn't follow your advices blindly but just takes your opinion and the observations behind it in consideration. For some people that can't handle advices the right way a misleading (and the chances it's misleading are always high) advice can be very harmful but for others advices from reasonable people that know what they're saying can be a valuable source of information. Anyway, that was me who has told him "my opinion is you should buy this flat now!" to remove his hesitations and it turned out a huge win, I feel like I should also provide a clue when to sell to secure it perhaps.