I don't know if the same thing happens to you as to me, and this is something that I understand only happens to people who are not merit sources or top earners.
I have seen legendary members say that they have a hard time finding posts to merit. In my case it's the opposite, I have less merit than I would like to send. Sometime, seeing a post worthy of merit, I've thought: well, as soon as I get the next smerit, I'll come back to this post and give it a merit. What happens is that if time passes, days for example, in the end I don't come back. I have decided that when I get a smerit, instead of meriting a previous post, I keep surfing the forum and give the merit to the next post I find worthy of merit.
Do you do the same or how do you do it?