Thanks, sometimes I use the denoiser but I don't like the loss of detail it entails.
If you look at my renders on here, I use the following settings on most of my posts you see. If I have a lot of detail in an image, I will sometimes bump up the iterations, but for the most part, this turns out quite nicely with very little difference in quality. It certainly looks better than a grainy image.
These are the main areas I changed. I'll explain more below this...
For "Filtering", I changed the "Pixel Filter Radius" to 1.00 rather than the default 1.50 as that leads to slightly sharper images without it looking too aliased near the edges. I set the "Post Denoiser Start Iteration" to 400, which is the number of iterations I usually render for. If you decide to do more, like say, 600 or 800 (which I will do for more complex scenes) than I change this to that number so that it only denoises on the LAST iteration and not during the whole render.
For the "Progressive Rendering" section, I set "Rendering Quality Enable" to "OFF" (it defaults to on) and I set the "Max Samples" to 400 (again, I sometimes change this to 600 or 800 depending on the complexity), which should be set to THE SAME number that you use in Filtering).
You can experiment with how many iterations YOU prefer as we're all different. You may want 1000. What I recommend is that you do a normal, full render without denoising, save it. Then do several renders with denoising with various levels of iterations and then put all the images in a folder so you can quickly switch between them and check out the difference so you can see if it is worth it and which one gives a nice quality in a respectable amount of time. I used to do only 100 or 200 iterations on my slow, limited memory GTX1050 card and posted them all the time in here and they were good enough.
The following render is just a headshot I did of my Sasha character I posted earlier. It was done using my standard settings I screen-shotted above. Actually, I have her loaded now and literally just took those screenshots from her settings. I think her quality looks great...
Edit: Oh, and one more setting I used for this render, is I set "Saturation" in the "Tone Mapping" section to 1.50 so the colours are more vibrant. But that's unrelated to denoising.