But how many of you will be reminded of those great times by this selection of photos?
They show the Plessey sports day, factory visits and plenty more besides.
You will, of course, have your own memories of the workplace and the people who worked there.
So take a browse through our photo spread and get in touch if you have memories to share.
1. In the picture in 1977
Plessey workers were pictured after a union meeting in 1977. | JPIMedia Resell Photo: Sunderland Echo
2. Time for fun in 1975
A scene from the Plessey sports day in 1975. | JPIMedia Resell Photo: Sunderland Echo
3. Ballet came to town
Ballet stars Wendy Roe (left) and Norma Atallah display some of their skils to machine operator Len Hunter on a visit to Plesseys in 1975. Remember this? | JPIMedia Resell Photo: Sunderland Echo
4. Wheelbarrow racing
Another scene from the Plessey sports day. | JPIMedia Resell Photo: Sunderland Echo