I am a physicist and most of the computing codes I deal with are open source projects that need to be compiled from source.

No.

I usually do it if the application I need is not in Slackbuilds.org, or if its version in very old.
I remember now any of them: amule (last version), some libraries, even I compiled libreoffice (last version too).
I compiled my own kernel once a time for slack (in order to learning, whit a pretty kernel panic in my first attemp), and I used Gentoo Linux for a couple of months, all compiled by yourself, as you know (another good way to learn to me).
I only think I hope nothing breaks during the process, because I don't know who to resolve the issue.

I started with Slackware v. 10.

Of course I've compiled from sources.

The kernel, way back when, and many others

No. I never compile a source code.

Does compiling linux kernel count? Apart from that, some applications when I used Slackware, and some windows app I did not find in binary form.

Yes. I have compiled LFS-7.x, LFS-8.x and currently LFS-9.0 many times. In BLFS, I have compiled Firefox, Seamonkey, MPlayer, Xine, VLC etc.

Patching and compiling some kernels from source before 2000 (Slackware distribution) and kernels afters 2000.

i don't it

Yes, several times ... including in the past various scientific s/w on an institute server (there should be e-mail's from 1990 from me somewhere on the net). Among the stuff I do sort of regularly at a new system installation (which I do seldom, every 5 years or so) there is the Alpine mail user agent, the Hessling editor (THE) and related libraries, and GDL, the "GNU data language", a clone of IDL.

In general I prefer if I find an already compiled binary for my distro (opensuse), but if there isn't or the bundled one does not satisfy me, I rebuild. For instance for Alpine I want the "all-patch" version (with user defined keys for instance) which is not usually bundled, and for THE I want the Xcurses version and not the plain terminal one.

I went through a period, when I started using slackware, when I used to compile the kernel, from kernel.org , in order to keep it updated . It would take me hours to read the documentation alone. Then I descovered slackpkg and found that I could update my entire system in less time than it took to compile the kernel.

i did compile for example conky with nvidia support which were unavailable from repository of my distro.
and i have compiled numerous progs (honeypots and etc).

ReZound (http://rezound.sourceforge.net/) and Jubler (https://www.jubler.org/). The former for sound file creation, conversion and editing and the latter for subtitling videos. Some others also, but these are the ones I have enjoyed the most.

Yes. I compile a lot of the source code I get from open source applications because I am usually adapting it for my own applications. Also, many times the open source app does not just plug in and work for one reason or another, and I have to compile, debug and recompile it several times just to get it to run on my system.

--pytheus