I use the mixer service once every four to six months because I don't have any black money to clean. I usually earn Bitcoin from forum signature campaigns, and I don't think it is worth using Mixers every time because I don't have that much money to spend as well. Considering you do not have too much money, you should not spend money by testing the mixer's services unless they pay you for it.
Once I am convinced of a service that suits my needs, I don't think it is necessary to look for new mixers unless they offer something better. Most mixers have the same job to do. It's unlike casinos, where I may look for special bonuses or features. I am being honest; I don't believe what you said.
I work as a crypto freelancer, translating and compiling documents. I get paid 50% in BTC and 50% in USDT. I can't trace the exact origin and history of these coins, and I want to avoid any legal issues, so a mixer seems like a safe option. I also don't want to waste a few dollars on monthly transaction fees, that's enough to buy groceries for my family.
I'm not one for experimenting, I just need a mixer with fees and mixing times that suit my needs. As you said, mixers are pretty similar, but they each have their own ways to attract users, like transaction fees, minimum and maximum BTC amounts, and mixing time.
And you don't need to trust me, you need to trust the mixer, like Coinomize.biz, when mixing your BTC.