In any hobbies, I think its good to set some rules for yourself. These rules will be your guideline and allow you to stay focus in the hobby.
In my miniatures collection, it did occur to me to collect other brands of miniatures and paint them, but there are just too many other miniatures brand around in the market. Some of them are sculpted so much nicer than the current brand I am collecting. Tempted as it could be, but I decided to set a rule for myself, I only collect miniatures from Gameworkshop and thats it. So far, my entire collection have been all from Gamesworkshop.
Besides the quality of the miniatures, sometimes the fluff or we refer to the stories, about the characters and the world itself also play a part in deciding whether you like or not. For some, they don’t bother, they just collect without knowing any of the stories. To me, stories are important, they play a part in our life, a part in our imagination, otherwise life would be so stale, right? I mean with stories, when you paint your miniatures, you can feel how the model would have felt or imagine the scenario the model is in, and once the miniature is completed… Wow, the satisfaction is so great and add on the imagination, you can feel how your favourite character would have felt…!
With rules set by yourself in collecting, one and stay focused and not be distracted by other stuff. Yes, I do agree that sometimes there are new brands and new choice that comes along, but think about the rules, then you will stay focus. In anytime, if you want to adjust your rules, then remember to ask yourself, is this collection which you are collecting, the reason is because you like, or are you just collecting for the sake of collecting. It make a big difference between these two choices. If you are collecting cos you like, then I think its reasonable choice you can decide. However, if you are collecting cos you just want to buy and fill up the collections, then I think you should re-think your purpose of collecting. This rule applies to any form of collecting hobbies. So, when one is not focused, sometimes you will end up collecting for the wrong purpose, and also end up having a lot of wrong decision and choices of piled up collections. Just remember to check and ask yourself on and off these questions when you are tempted to.