Here's the reality: for virtually field, it's impossible to collect it all. Romance novels, coins, dolls, stamps, Civil War memorabilia -- there's just too much.
Someone I know "collects" pigs. Well, it's something she's passionate about, but there's no focus to her collection. Anything that's generally pig-shaped is fine with her, from the cheapest plastic knick-knack to expensive crystal sculptures. It's not so much a collection as a pile objects indiscriminately thrown together.
Museums have a plan for obtaining objects, and so should the collector. Museums are after things that fit into their overall mission, that helps tell their story. A museum that's focussed on 19th century life may have a few contemporary newspapers to help illustrate daily life. A newspaper museum would have thousands -- but none of the 19th century clothing, furniture, etc. that the other museum would have. Both museums could have the same objects, but use them in different contexts.
Same with personal collections. Having a focus makes the collection manageable, and at the same time gives it a purpose.
Let's go back to that pig collection. Currently, it suggests someone who's a borderline hoarder. But suppose it had a little focus. In addition to her affinity for pigs, she likes crystal. Combining those two passions, she could collect only cut or blown glass pigs. It would actually make each object mean more to her, and also tell a story of her interests. If she liked a particular studio, or school of design, she could further narrow her collection, while increasing its interest not only to her, but to others as well.
The more focussed a collection, the easier it is for non-collectors to understand. I'm not saying you should collect for the approbation of others -- collect your passion. But you can communication that passion, and perhaps pass on an appreciation of your interest to others if there's a purpose to your collection.
A collection of 19th century cast-iron piggy banks is tells a story -- several, actually. This is the level of technology for these type of objects in the 1890's; this was the shared cultural perception of pigs; this is an example of 19th century life; look at the variety of form and quality in these pieces all made around the same time.
And having a focused collection makes it easier to decide what belongs, and what doesn't. That doesn't mean you have to be draconian -- it's your collection, you make the rules, and you decide when to break or bend them. So that collection of cast-iron banks may have a lone plastic piggy bank from the 1950's, the bank the collector owned as a child, or perhaps was given by a dear friend.
And it's best to decide on the focus of your collection as early into the process as possible. It's always easier to not bring something into the home, then to try to get it out again -- and more economical, too.