It’s worth thinking through how you will maintain your languages once you have them. For instance, you maintain your English by using it every day. Other languages often demand a more deliberate approach.
I am now maintaining French, German, Spanish, Thai and Italian. The combined vocabulary is roughly 40,000 words. I invest 20 minutes per day in maintaining those languages and 20 minutes a day in improving my Italian and my Thai. My maintenance time may sound quite high but it is only 4 minutes per language. Anyone who is maintaining non-native languages is putting time into maintenance. How is it possible for me to maintain so much information in so little time?
Because the day I started, everything I did was working towards minimising the long term cost of maintaining my languages. The system of “cram and dump” promoted by academia can get you through an exam course – maybe – but it won’t allow you to minimise your time retaining full use of your languages. If you don’t maintain your languages your efforts will have been lost.