The paper discusses the role of nanoscale phase separation in manganites and its implications for high-temperature superconductors (cuprates). It highlights that the colossal magnetoresistance (CMR) effect in manganites can be understood through the competition between charge-ordered and ferromagnetic phases, which also occurs in cuprates. The authors review experimental evidence of intrinsic inhomogeneities in manganites and cuprates, emphasizing the presence of nanoscale clusters and domains. They propose that these inhomogeneities lead to observable consequences, such as the CMR effect in manganites and potentially similar phenomena in cuprates. The paper also explores theoretical models that describe electronic phase separation in manganites, where the competition between ferromagnetic and charge-ordered phases results in a discontinuity in carrier density. This phase separation is robust and has been observed in Monte Carlo simulations. The authors extend these findings to cuprates, suggesting that the pseudogap temperature and the spin-glass regime in cuprates could be related to the formation of clusters and the Griffiths temperature. Additionally, the paper discusses the potential relevance of quenched disorder in cuprates, which may play a more significant role than previously thought. It suggests that careful sample preparation to minimize disorder could lead to higher critical temperatures in cuprates. The authors conclude by emphasizing the importance of understanding the phase competition and inhomogeneities in both manganites and cuprates to advance our knowledge of these materials.The paper discusses the role of nanoscale phase separation in manganites and its implications for high-temperature superconductors (cuprates). It highlights that the colossal magnetoresistance (CMR) effect in manganites can be understood through the competition between charge-ordered and ferromagnetic phases, which also occurs in cuprates. The authors review experimental evidence of intrinsic inhomogeneities in manganites and cuprates, emphasizing the presence of nanoscale clusters and domains. They propose that these inhomogeneities lead to observable consequences, such as the CMR effect in manganites and potentially similar phenomena in cuprates. The paper also explores theoretical models that describe electronic phase separation in manganites, where the competition between ferromagnetic and charge-ordered phases results in a discontinuity in carrier density. This phase separation is robust and has been observed in Monte Carlo simulations. The authors extend these findings to cuprates, suggesting that the pseudogap temperature and the spin-glass regime in cuprates could be related to the formation of clusters and the Griffiths temperature. Additionally, the paper discusses the potential relevance of quenched disorder in cuprates, which may play a more significant role than previously thought. It suggests that careful sample preparation to minimize disorder could lead to higher critical temperatures in cuprates. The authors conclude by emphasizing the importance of understanding the phase competition and inhomogeneities in both manganites and cuprates to advance our knowledge of these materials.