Isabel Ordaz left the show at the beginning of season 2 in order to work in theatre. When she returned for season 5, it originally a one-year contract, but the writers/producers enjoyed working with her again so much that offered her a renewal. She agreed as long as she could continue to do theatre, which explains her absences in seasons 6, 7, 8 , 9 and 10.
According to co-creator Laura Caballero, the opening credits weren't use since season 3 because it was expensive to create new cartoons every year (many actors left and arrived the series on season 1, 2 and 3) so they just displayed the cast names.
Luis Merlo refused a role written for him arguing it was too similar to his character on Aquí no hay quien viva (2003). Years later he would appear in the show, but in a completely different character from his famous Mauri.
To this date (December 2017), more than 30 actors who had significant roles on Aquí no hay quien viva (2003) have appeared on La que se avecina, either as regulars or just guest actors. The list includes Malena Alterio, Gemma Cuervo, Mariví Bilbao, José Luis Gil, Emma Penella, Fernando Tejero, Guillermo Ortega, Sofía Nieto, Eduardo García, Eduardo Gómez, María Adánez, Isabel Ordaz, Eva Isanta, Elio González, Adrià Collado, Juan Díaz, Carmen Balagué, Vanessa Romero, Beatriz Carvajal, Roberto San Martín, Ricardo Arroyo, Nacho Guerreros, Jaime Ordóñez, Pablo Chiapella, Jordi Sánchez, Jesús Olmedo, Marisa Porcel, Santiago Urrialde, Dani Muriel, Luis Merlo, Loles León or Laura Pamplona.