There is a small two partner legal firm that I know.
They have four clerks and an accountant. The firm started when the senior partner went out on her own and typed up her documents herself as the clients sat in front of her and answered the necessary questions. Conveyancing occurred in days and weeks, not months.
Clients loved her. The service levels and speed of her process made her so successful and sought after she had to expand, take in a partner and gophers. All the machines in the office are Xt's or 286's using Wordperfect 5.1 and Canon Bubblejets.
Each machine is set up with "standard" boilerplate forms in subject directories. There is no LAN. In the unlikely event of the girls wanting to share a new file, they swap floppies. There is not a Window in the place, except for in the walls. They use dates but in a secondary sort of way.
They can use their systems until the end of time. They have no BIOS dependencies. The DATE command allows for YYYY/MM/DD entry from 1980 thru 2099. They will not have rollover problems on the 31st December 1999 because they will change their dates manually. Once.
For our purposes, let us define this small legal firm as a "Class 1 Y2k object".