Relationship points decay if neglected. A common mistake is focusing on one girl and ignoring the others, only to find that the ignored girls have reset to zero. While it is difficult to "max out" all three girls in a single playthrough without deep knowledge of the game, it is possible to maintain them.
Common love interests:
Crucially, the game features holidays (such as Valentine’s Day and Christmas). These dates are pivotal "checkpoints." Successfully asking a girl out on a holiday results in a massive boost to the relationship meter. Failing to have a date on these days, or being rejected, can be a run-ending mistake. Therefore, players should plan their relationship meters to be at "Close Friend" status or higher before these major calendar events arrive. simgirls walkthrough
To get the "Harem Ending," you must have a Love meter of 100 with at least three girls simultaneously before Day 80. Relationship points decay if neglected