Residents have occupied flats before the builder has completed all work, with around 20% remaining. The developer is suggesting forming a society, but residents fear this might lead to the builder abandoning the remaining tasks. Experts advise that the builder is legally obligated to finish all work and is liable for any delays or failures. While forming a society with only a portion of flats occupied is legally questionable, it's suggested to proceed with a clause ensuring future owners join. Alternatively, forming a society rather than an association is recommended.