With decent but not great hands, it is very often worthwhile checking in front on the river even when you think you are ahead. There are two reasons - one, you avoid a raise from a better hand; and two, you will very often induce a bluff from a weaker hand.
Example, suppose you hold 88 UTG. You raise preflop, and all fold around to the BB, who calls. The flop comes out A76 rainbow. This is a pretty good flop for you, so you bet and the BB calls. Turn 2s making two spades on board, you bet again, BB calls. Now on almost any river card, it is probably worth check-calling rather than leading. If the BB has a busted draw, he will certainly fold. If he has a small pair he might call a bet or he might fold. A hand that beats you will raise, costing you two bets instead of one, while a weaker hand may put out a bluff bet if you check. A check is especially warranted if a scare card such as a spade or a king comes on the river, because it is reasonably likely to have made your opponent a better hand, and also it gives more incentive for a weaker hand to try and bluff.
This is a play I don't think I have engaged often enough, but recently I have been noticing just how often players will stick a bluff bet out with nothing on the river. A bonus on sites where mucked hands at showdown are not revealed is that you get to see their hand if you call their bluff bet!