Python trademark at risk in Europe

Registered trademarks aren't free - a UK trademark costs £200 (£170 if you're prepared to apply via the online forms) for your initial application in one class, and £200 for each renewal (every 10 years). Add an extra £50 to each fee if you want to hold the mark in multiple classes.

It's generally more sensible to rely on unregistered trademarks - the fact of use of a trademark is enough to establish it such that you can either reclaim the trademark yourself if someone else applies and you think you can show you're using it (£200 fee), or have the IPO declare it a "generic" mark (£200 fee). You can also (£200 fee for this) have an existing trademark removed due to non-use.

Basically, costs of registering your trademark for 10 years are about the same as stopping someone else from obtaining it or using it. You might as well wait until you need to claim it before you do so - it's similar cost, and that way, you're not out the price of a reasonable SSD every time you start a project.