Almost always I have raised forces that fight each other starting way back in the 1960s with Airfix British and Germans and since then many other periods and campaigns. Since I started with these they have remained my main interest even though they seldom take to the table now. I start a “new” collection when I become particularly interested the history of a campaign and I always built opposing forces. Only once did I raise a one sided collection – Belisarian Byzantines, I was studying the campaign and on impulse bought a small army. When we had kids they played GW fantasy and I bought and painted armies for them – I have just sold them off as I needed the space. Now we have grandchildren and I am building “armies” that they are interested in – zombies v survivors, Bolt Action British v Germans and Russians v Germans in 28mm. My collecting is focussed on the Dark Ages Britain and refurbishing my old school fantasy figures.
This has been useful in the current situation as I have everything I need to play solo. And these solo games are the motivation to keep my current project of Dark Ages Britain going. Though I am playing zombie games as they are easy to set up and play and because the zombies are “programmed” and governed by random cards every game is a different challenge.