How to tell when you have too many trees
From BonsaiWIKI
Bonsai is a process of continuous improvement, this often means that the time you'll need to spend with your trees will increase as time goes on.
The time required to maintain finished trees in top form increases with the number of twigs.
To get an idea of the number of trees you can reasonably maintain, you'll need to ask yourself how much time you can afford to spend with your trees on a daily basis. There's much less to be accomplished in winter, but you can expect during the growing season you'll need to spend approximately 30 minutes a week with each tree, and possibly more, depending on the level of development. This might amount to five minutes' time to water and inspect, five minutes for weeding, 15 minutes for chores like pinching and trimming and some time for repotting and (un)wiring.
So as a rough rule of thumb you can take the number of hours you have per week for your trees, double it, and that's approximately how many trees you should plan to maintain in bonsai form. If you have 10 hours to spend per week, you might maintain up to 20 trees in top form.
TIP: Early on, having a number of trees of a similar kind in different phases of refinement may offer the beginner the opportunity to practice techniques (like decandling pines or wiring) until the skills become instinctive. You'll also have the opportunity to compare two trees given different variations of soil, fertilization or technique and determine what works best for you and your climate.
TIP: The idea of raising a number of trees from saplings or seeds to to maturity in order to "cash in" on bonsai may be attractive at first, but you should understand that it's a very difficult way to make money. You'd probably do better by taking roughly developed stock to a moderate level of refinement and then selling them. Perhaps better still would be to bury the money in your backyard!
