I've been back into Saltwater for about three years now. I'll be honest, it was so much simpler 15+ years ago and so much more affordable.
The first two years I got back in I listened to a LFS owner, as well as an online owner, and a few others. Unfortunately, it's cost me about $45k in fish.
I was told "I've set up a ton of tanks and used this bacteria in a bottle and it's successful every time."
Cost me a M+F pair of Japanese Dragons.
I also made the mistake of purchasing fish from a LFS owner before they were quarantined. 4x Kingi Angels, actually, and they killed all of them then told me they couldn't afford to refund me.
I started quarantining fish myself and there is a huge learning curve to that. I probably lost half the fish the first 6 months.
It's not even the money that bothers me. I'm not hurting. It's the sleight of hand I've gained at the cost of a ton of life for selfish purposes.
I have my 400 gallon and I have a few high end pride and joys in there, but I'm done adding. Even many of the ones I successfully get through quarantine, end up passing for no apparent reason months later.
I've learned that almost all LFS understand that most people are in and out of the hobby so they just need to make the quick sale.
I've played dumb with one of the locals, Rick's Fish and Pet, in Frederick, MD. He'll tell you anything to make a sale. I bought an Icecap scrubber online and he started screaming at me in the store, in front of customers, that it was garbage and I should've bought one of his CWs that are all marked up much higher than online. I told him his prices are high. He said he needs to do that to compete with online retail. Maybe get with the times. Also, keep in mind, this guy is the one that sold me on the bacteria in a bottle, and I spent $5000 a week prior on two Dragon Eels and a bunch of equipment.
I haven't spent a cent since I'm that store.
I found my way, and I hardly lose any fish in QT now, but I had to figure it a lot out on my own with trial and error.
Prime, dose bacteria... Every day. Run a D.E. filter 24/7.
Main display, don't feed pellets, limit the Tang population (3x Koi Scopas tangs all brutally murdered by one Purple Tang.)
I have one more big marine fish purchase happening, over $100k and I'll mention it later next month, but overall, I'm done with anymore fish in the DT, quarantining, etc.. It's wasteful.
I've been getting back into freshwater. I just bought my first ever Flowerhorn and attempting to groom it for competition. I plan to setup a Zebra Pike Cichlid tank and maybe an indoor Stingray pond.
I never, ever, lost freshwater fish. I don't care if it's less challenging and not as beautiful, it's just not worth the death anymore to me.