If you prefer to save some money, or prefer a scenic longer ride over a fast one, you can easily choose train routes without seat reservation requirements. There are a couple of ways you could go about this.
The Railplanner App
The Railplanner app allows you to plan your journey without having to travel on any trains that require reservations. When entering your trip in the Trip Planner, go to ‘options’ and switch on the ‘No seat reservations required’ button. The planner will then only display trains and routes that do not require any reservations. When you want to see the quickest suggestions again, you can simply turn this filter off again.
Travel To Countries With Little Seat Reservation Requirements
Many countries have little to no seat reservation requirements, so there's no need to pay extra to take a train here. Some of the countries with very little seat reservations are: Belgium, Luxembourg, Netherlands, Switzerland, Germany, Austria, Czech Republic, Denmark, Great Britain (often needed, but free of charge), & Ireland. In Eastern European countries, some trains have reservation requirements while others don't. For a full overview per country, please check out the Train guides on the Interrail website.
Check the Interrail Pass Benefits Portal
The Interrail Pass offers tons of discounts on hostels, tourist attractions, and means of transportation. On some routes, the Interrail Pass might offer a discount on e.g. ferries or bus services that could offer a suitable alternative to an expensive seat reservation. For a full overview of this, please check out the Interrail Pass Benefits Portal.
Ask the DiscoverEU Community!
You can always ask your fellow travellers for some advice when travelling, and you can find them all in the DiscoverEU Community! Someone might be from the area you're travelling through, and could have nice recommendations for stopovers that you might not have otherwise considered. Others may have travelled the same route, and found a way around the reservation requirements.