Yes, that may very well be the case, and this is desirable.
A quick example. Let's say you only use one receiving address to which you send 0.1 bitcoin every month for twelve months. Then after a year you will have saved 1.2 bitcoin at that one address. Suppose you then buy something worth 0.1 bitcoin, your wallet will generate a transaction in which 12 pieces of 0.1 are sent out to two addresses. Of these, 0.1 BTC goes to the seller and 1.1 BTC goes to a new receiving address you control. However, because the transaction is public, the seller can see that you still have 1.1 bitcoin in your possession. This may be information which you would prefer to keep private.