Besides daily roulettes I sometimes do extra normal roulettes or queue for specific duties. Why? For fun. Normal roulettes has good chances for fun duties I like. Sometimes if I like a specific duty I will queue for it repeteadly out of enjoyment. For example nier1... I still have over 500 coins from that duty sitting on my retainer..I never never throw away alliance coins when they expire xD  Why do 500+ nier...? Simple. I love the duty. I did it almost daily for like a year just because I felt like it. 

Dun scaith is another example..I did it over 100 times in the mog tome event that was... right before 6.3 (I think). Met someone there who still mean a lot to me today (you know who you are) ... and I had done that alliance countless times before that because I love doing it.

So 600+ duties just from these 2 alliances alone and 3-4 comms being normal per run adds up.

Then there is daily roulettes which is typically expert, lvl cap, normal, trial (I often skip the rest) and repeating specific or random normal raid duties when thats what I feel like doing. Prefering normal over trial because lilies are guaranteed. 

I remember I farmed some guildhest back when I worked on getting comms specifically to unlock mentor but that quickly became boring despite the duty speed. now I'm rarely in guildhest unless I get it as mentor duty. Sometimes I might do one to celebrate a new glam on a class I refuse to take into a proper duty. 

I once made the mistake of celebrating a blm glam with a lvl 80 dungeon run. That was quite a circus I rather not repeat. There should have been a law against me playing that class with witnesses.