Even irregular troops have a payroll to meet, and when the money runs short, the troops start running away. The latest rebel organization to find that out is the communist ELN of the Philippines. The ELN is now replacing a growing number of deserters, with kidnapped teenagers. This is a common tactic with cash strapped irregulars all over the world. The ELN ran into money problems after September 11, 2001, when it got tagged as a terrorist organization. It always was, but leftist sentiment in Europe and the UN enabled the ELN to avoid the designation. That's important financially, because it meant the ELN could raise money world wide. Within the Philippines, it raises cash with the usual (for rebel groups) extortion ("revolutionary taxes") and outright theft (more "taxes" for the revolution.) However, the loss of the overseas funds was felt throughout the ranks back in the Philippines. Extortion activities were increased, but that could not make up for the shortfall, and desertions began to increase. That led to debates among the ELN leadership, which has produced some dead bodies (of people who lost some of those debates).
Kidnapping teenagers, and indoctrinating/coercing/brainwashing them to become fighters for the revolution is second best to having adults. Morale among the kids is more fragile, and their inexperience and immaturity makes them more difficult to use in combat. But, as experience has shown, the kids will pull the trigger as readily, if not as steadily, as an adult. Once you start using kids, however, you are taking a step backward, and likely to be on your way out of existence. You need to change the minds of adults, not teenagers, if you want your revolution to succeed.