Each time Patient Rebuilding’s triggered ability resolves, it counts only the land cards put into that graveyard during that ability’s resolution. For example, if your opponent puts two land cards into their graveyard during one upkeep and three land cards the next, you’ll draw two and three cards, respectively, not two and five.

If your opponent moves cards from their library but they aren’t put into their graveyard (perhaps because you control Rest in Peace), you won’t draw any cards.