I think I did a secondary once ..... now about 100 batches later I have never seen any ill effects. However the once time i did it was a beer that was conditioning with some fruit, so the idea was to have it sit on the fruit purée in the secondary and off the yeast cake which made good sense. The less I need to move the beer around the better. Now it goes from the primary into the keg under co2.
It’s a fun hobby though for sure. I am a bit afraid to add up all I have spent ....... certainly not doing this to save money. But it’s up to you and your self discipline as to how deep down the rabbit hole you go. It makes life easier if you have a temp controlled chamber to control fermentation and then later to cold crash. I bought a small chest freezer for a couple of hundred bucks and added a 30 dollar inkbird temp controller to it and it has been awesome.
Lots of info and advice on this site as well, its been a huge help for me ( I started maybe 3 years ago I think). also check out the Brulosophy web site and podcast.... they do lots of great “exbeeriments” testing many theories and long time beliefs and myths.