I mean when people had forgotten it was a spin-off of DS and when people arrived to the point that Charlotte Rae (and Mrs. Garrett) was better known for being a housemother and dietitian in a private girls' school rather than Philip Drummond's housekeeper who got her own show (although Mrs. Garrett was probably the best known of the three housekeepers of DS). For me, it was by season 3 or 4, when DS producers hired Mary Jo Catlett as a permanent replacement for Rae and when the actors/actresses of both shows didn't do crossover episodes anymore. The first two seasons were related to the parent show because they still had to find an audience. Even the commercials said: "Mrs. Garrett from Diff'rent Strokes takes over a dormitory full of girls". What do you think?

I mean when people had forgotten it was a spin-off of DS and when people arrived to the point that Charlotte Rae (and Mrs. Garrett) was better known for being a housemother and dietitian in a private girls' school rather than Philip Drummond's housekeeper who got her own show (although Mrs. Garrett was probably the best known of the three housekeepers of DS). For me, it was by season 3 or 4, when DS producers hired Mary Jo Catlett as a permanent replacement for Rae and when the actors/actresses of both shows didn't do crossover episodes anymore. The first two seasons were related to the parent show because they still had to find an audience. Even the commercials said: "Mrs. Garrett from Diff'rent Strokes takes over a dormitory full of girls". What do you think?

I think this was done on purpose because after the first two seasons of FOL, the child actors of Different Strokes were complete train wrecks and the writers of FOL wanted to distance itself from it's parent show and give it it's own identity.

Once Facts of Life became a ratings success in its own right, there was no need for further crossovers to pump it up.

I think the final connection between FOL and DS might have been Drummond's wedding, DS episodes 6-20 and 6-21, which corresponds to Season Five of FOL. This was the last episode when DS and FOL cast-members interacted, except perhaps in flashbacks.

After that, I'm not aware of any crossover attempts. By this time, DS and FOL had clearly grown apart, Mrs. Garrett now several jobs removed from her time as a housekeeper in Manhattan, and Mr. Drummond unwilling to drive out to Peekskill for some delicious quiche and warm apple strudel (his loss!).

Still, we had five good years of DS/FOL crossovers, with characters crossing over in Season DS1/FOL0, DS2/FOL1, DS3/FOL2, DS4/FOL3, and DS6/FOL5.

Of course, an argument could be made that the crossovers really faded out at the beginning of DS4/FOL3, when Kim did her last few DS episodes; this was also right around the time that the Lost Girls got their final episodes. By Season 4, it seems, the producers wanted change, and that meant cutting most ties with the early history of the Facts of Life.