I've recently travelled in both Iran and Poland.

I've never done it before, but in both countries at various times I hired private tour guides. And in both countries, the experience was really great. They, unsurprisingly, knew a whole lot about their home cities and the interesting things around it. In some cases they had cars and could drive me to places that I wouldn't have been able to get to otherwise. One was an official guide for a restricted forest.

It's definitely something I'll be doing in the future.

Can I ask if anyone else has experiences and/or general impressions of hiring private guides they'd like to share?