I have been afflicted yet again with another bout of Wanderlust. If you are unfamiliar with this wretched condition, let me explain. It haunts those of us with an interest in many languages and makes us do what we most want to do but is the least efficient - move on and start to learn another language before the last one is learned to a sufficient level.
This would be fine if our goal was just to get a sampling of a language and then move on to another. Some people like to do this just to get a taste and I recommend it once in a while just to change things up - see my article Trying Out a Language.
But if you want to learn a language to a serious level it can be dangerous and counterproductive to move on before you are ready.
Wanderlust afflicts some language learners in a chronic fashion. They just can't seem to finish study of one language before moving on to another. In my case (the most recent case anyway), I have taken advantage of a course in Old English before I have reached my mid-term goal in Dutch, and of course before I have properly retrenched my French. I couldn't have a conversation with a baguette at this point.
Old English was such a demanding class (along with my other classes) that I basically neglected all other languages during that semester. While that knowledge of Dutch helped me in Old English, and learning Old English will help in my knowledge of Dutch and other Germanic languages in the long run, in the short to mid term, I ended up delaying reaching my goal in Dutch. Only very occasionally did I guiltily engage in a few minutes of study or listening to Dutch, French, Spanish or anything else. But, of course just a little once in a while is not effective for moving forward in a language, and it is not an effective strategy for maintaining a language for more than a short while. More steady application is required.
Anything that distracts you from your goals is dangerous. Wanderlust can be very tempting and it's easy to give in to its twisted logic. Every time I hear someone speak in a language I haven't studied, it rears its ugly head. Try not to give in to it, or at least, work it into your long-term plan. Whatever you do, don't let Wanderlust interrupt or change your plan too much.