In my opinion you should leave the CPL off unless you specifically have a reason for it. Youve got a great camera and a pretty good lens so I wouldn't add any more glass to the combo unless it was necessary for a particular reason. Dinner parties it is more hassle than its worth and not necessary. Sunsets you will be near to shooting at the sun so a CPL isn't going to have much affect, leave it off. Landscapes it a genre where it can give you a number of reasons to use it.
Rather than going into the effects and reasons for use here, I suggest you do a google search 'how to use a CPL filter' and you will get a lot of stuff to study and said much better than I could phrase. Also a search on YouTube with just CPL filter, will give you some very helpful results.
I subscribe to this guys channel. He's a so called 'pro' landscape photographer and I think gives excellent advice in an easy way to follow. Here's one on what he thinks of a CPL filter https://www.youtube.com/watch?v=0E1nwQgmIAk

Enjoy the journey

Little is understood by many photographers about how a polarizer can be used to advantage.

First, understand that there is more to winter tan cold weather. In Summer the earth is further to the sun than in winter. The angle of the earth is different in winter than in summer, and the earth is closer to the sun sun in the winter. It is part the angularity of the sun combined with proximity and the structural structure of earths atmosphere.

When you combine these factors you get a rather fascinating effect. these factors can be used to rather interesting effect. But first you need to un-learn some of the rather pedestrian ideas that are persuaded as 'truth' in photography. Essentially, most workers in photography are caught up in rather 'cherry picked' notions of many principals that are etched in stone. What you need to do is go look and develop independent ideas for principals in photography that are more empirical*. I know, big word. Essentially it means you look ad observe with a new look at what is before you then ignore what you are being told and use your practical experience and then decide what is actually being shown to you.

* empirical:
"based on, concerned with, or verifiable by observation or experience rather than theory or pure logic."

First, learn about the silly ideas that people will tell you, "Polarizers remove reflections", This is absolutely not true. Take the polarizer off of your camera stand in front of a mirror and rotate the polarizer till your arm hurts. Your reflection stays in full view (unless of course you are a vampire then polarizer or not you will have no reflection what so ever).

Go outside and find an old automobile (or a big trailer hitch with a chrome ball), and look through the polarizer, note that just like a mirror, your reflection stays right there in the chrome mirror surface. The polarizer does NOT remove the reflection in the chrome. You may want to get a chair and get comfortable for this part. Using chrome surfaces or a mirror will do just fine, slowly rotate the polarizer and be empirical, look carefully at the objects that are all around the reflective material in your view. Note that as you rotate the polarizer that there will be some, we lets call it correctly, anomalies they will appear as haze laying between you (the polarizer) and the thighs that you are looking at, as you rotate the polarizer you will observe that this 'haze' will weaken or even be removed mostly.

Now his the part that will kick you in the head, that haze between you (polarizer) and the object (s) will be more pronounced in the shade than in the sunlight! You will need to trust me on this next part, but if you like find a truly deep hole (mine shafts are great fir this) in the ground that you can look up at the sky above you, you will see that there is no blue sky and you can see the blackness of space and loads of stars! (Of course, it only works if your not in a city with loads of polluted air, that is haze).

Of course everyone and you all so are just getting tired of reading all this. Sorry, I'm that actual master photographers who really does know my craft unlike the mostly silly people who think they know the craft!

Basic truths:
Polarizers are NOT filters, they are neutral density attenuators.

Polarizers can be used to manage haze, or scattered polarized light.

In the winter there is a butt load more polarized light tan in summer, in fact the polarized light is quite prevalent compared to summer time.

Here it comes, ready. If you extract the blue light from the sun lighted winter landscape you can reduce the haze in the landscape to such a degree that the landscape will appear to be almost with severally open shadow.

So, how do you do this trick? Remove the blue end of the winter summer sun from the landscape? Mount a polarizer on to your lens. Now add a Wratten (Kodak) no. 12 filter to your lens. No, the old 'G' filter, common know as the Wratten No. 15 filter, will not be enough to remove the blue end of the sunlight. The view you will have and can make as a digital capture or on film (I have done B&W images with this technique many times) and the results are stunning. With digital, there is no way I know to put the blue back into a color image, bit you can convert the final image to a great B&W.

Deep technical note for those who love technology, circular and linear polarizers have the same effect with photography... BUT ...of not, on a view camera you can mount the filter and polarizer inside the camera on the rear of the lens cell, you will find that when the Wratten 12 is used with a circular polarizer, the effect is lost, why I do not know. Linear polarizers work on the camera normally when mounted on the rear or front cell.

With apologies to the original poster, this question has provided me with several days of both humor and despair. It is remarkable that simple questions of procedure ALWAYS turn almost immediately into extended tirades of personal philosophies and almost scriptural sermonizing.

OP--I suggest you give it a try and see what works. Check for vignetting and make sure your polarizer still does whar it needs to do.

We're doing photography here. There's absolutely no reason for that to come with all the grief and stress that this forum brings. It's intended to be fun.