Don't ever get tired of something that gives you something.
A lot of people were spoiled brat divas, they were tired of something that gives them money, clothes, food and any other things that they needed. They were full of complaints they can't appreciate what they have, they can't appreciate the only thing that keeps them alive.
If your job is still giving you money then love it, nurture it and milk it as much as you can. A lot of people were jobless and they don't know where will they get some money. They were always in a very bad adventure everyday looking for food to eat. So if you have a job, even if it is not paying you well... love it. If you can look for another job and you are confident that you can find one that pays better than your current job then go ahead, but if you are scared to take risk then simply love your job and be satisfied with it. It is giving you something so keep doing it.
Not only in job or money, same with the other things... if it is giving you something then keep doing it. For example in training, if you have a specific drill that you've been doing for years and you are getting tired of it.... if you think that it is still giving you an edge and a little bit advantage then keep doing it. Never get tired of it because it is making you strong, don't get tired of something that is keeping you in track, don't stop doing something that gives you momentum, keep doing it until it is not serving you anymore.
A lot of people nowadays feels like they were kings and queens. Once they get tired of doing something and they don't feel the fun anymore... they will stop doing it. Success and living a good life doesn't work that way, you should never take something for granted that gives you money, energy and stability.