One should be fully absorbed in thoughts of Krsna, twenty-four hours a day.

There are many devotees in raga-marga, which is exhibited in Vrndavana. Whether in dasya-rasa, sakhya-rasa, vatsalya-rasa or madhurya-rasa, all the devotees of Krsna are always overwhelmed by thoughts of Krsna. When Krsna is away from Vrndavana tending the cows in the forest, the gopis, in the madhurya-rasa, are always absorbed in thoughts of how Krsna walks in the forest. The soles of His feet are so soft that the gopis would not dare keep His lotus feet on their soft breasts. Indeed, they consider their breasts a very hard place for the lotus feet of Krsna, yet those lotus feet wander in the forest, which is full of thorny plants. The gopis are absorbed in such thoughts at home, although Krsna is away from them. Similarly, when Krsna plays with His young friends, Mother Yasoda is very much disturbed by thoughts that Krsna, because of always playing and not taking His food properly, must be getting weak. These are examples of the exalted ecstasy felt in Krsna's service as manifested in Vrndavana. This service is indirectly praised by Narada Muni in this verse. Especially for the conditioned soul, Narada Muni recommends that one somehow or other be absorbed in thoughts of Krsna, for that will save one from all the dangers of material existence. Full absorption in thought of Krsna is the highest platform of bhakti-yoga.

(From SB 7.1.27 purport)