A few thoughts since I’d also be interested in exchanging information on prints here, with a focus on “our” applications (darktable, scribus etc).
First of all, amateur photographer here, for the past few years focused on my family; not fancy or short-term rewarding, but for me vastly more important than everything else – just to mention a name, one of my heroes is Sally Mann.
I use Linux and to drive my Canon Pro-100 (dye-ink) I have bought a Turboprint license. It’s accessible from darktable and the way I do prints are mostly 10x15 or 13x18 and occasionally larger (20x30, ~A4) prints. I don’t have to fiddle too much with the default settings to be hones to have a good and faithful color reproduction. I use original canon inks which I buy in multipacks from amazon (all 8 colors).
For throwaway prints, I use the standard canon glossy photopaper 100 sheets 10x15 pack; I also have a collection of various kinds of papers from Red River Paper, which are all fantastic (and not as expensive as Hanhnemule).
My experience is that for quick proofs and prints, having the possibility to print at home at any time and see the results immediately vastly outweighs the lower costs of cheap prints from a photolab. And the quality is very very good anyway, even on the cheapest paper that I have.
And when I need high quality prints, I don’t have the kind of expertise and experience and knowledge to have identified an exceptionally good and reliable professional printer locally.
I probably need to mention that I live in Milan, Italy, where surely there are high level labs and professionals… but having no affiliation to photo clubs or friends sharing the same level of interest in photography, I always have the feeling of bein ripped off when I occasionally seek an “expert” opinion or service.
So when I need to do a high quality print, I feel like I’m not let down by my Canon, and the fun you have by choosing different papers and see what is the effect on the print is invaluable.
About the reason to print, plenty of people have argued about the importance of looking at physical prints, and I will refrain to do so. I want just to mention that I’m very far away from the idea of prints as something to be put under glass; printing even on cheap paper is a way to judge the photos regardless of the little tiny technical details that I obsess with while pixel-peeping in darktable… it’s a good way to put things in perspective, to let go of the noise, the dynamic range, and all the other wonderful things I aim to get “right” when working in darktable but that are ultimately meaningless in terms of emotions and significance of the photo. Printing a stack of photos is also the best way to build a meaningful sequence (I can’t do that in darktable, but I’d gladly accept any suggestion you may have on how to do that).
Anyway, if we were to put on a printing section of the forum, I would like to discuss about how to properly use darktable+Turboprint, how to use Scribus to build photobooks that can be sent out to Blurb for printing etc (I have followed Andrew Milnor’s advice in the past and have had great fun in making photobooks on the cheapest papers offered by Blurb, just to have something physical to hold; I’m now making a similar book in Scribus trying to setup the pdf layout in agreement with Blurb’s requirements but haven’t done the last step yet – sending it to print!).