Not the parent but from my own experience having had companies in many countries: Spain was by far the hardest and most confusing. I only had companies (4) in Andalusia, so I cannot comment on other regions; where other countries are quite logical and I am usually able to reason with the tax auditors, in Spain it was hostile and most accountants, lawyers and gestors basically told us, time and time again, to just relax and do many illegal things as you will lose boatloads of money I'd you do not. However, I like sleeping at night as do my partners so with did everything by the book and it was extremely painful to do so. There are rules on rules on rules, deducting business costs are hard if not impossible etc. And you need help for everything: in Spain there is an industry called Gestors who are not accountants but people who help navigate the bureacracy. The Spanish use them as well and there are many all over the place. So you pretty quickly find out things work if you are a tiny company (autonomo) and just don't declare any tax (put it in your matress), hire people by paying them cash etc. Or you need to be a large corp with lawyers, accountants etc to navigate things efficiently. In between you mostly just get misery. I sold and closed the companies and the people that bought them since then burnt out and quit or just adopted what my Spanish friends call 'the Spanish way', which is, quite simply basically running almost fully illegally: having a 'broken' PoS all the time (so people have to pay cash), using black funds to pay people and goods and just showing losses all the time (paying only the autonomo social security and nothing more). I would find it impossible to sleep as I simply cannot accept the thought of the Guardia stomping down the door in a few years. My friends tell me I worry too much about nothing... maybe; I would never do it again.

Good to know is that Spanish taxes can go back 4 tax years which equates to about 5 years. This is shorter than most countries I did business in.