When there is a game i want to play. That could mean 4 a month, it could mean none

It varies, but it's usually one or two physical games at max per month.

I have previously checked my spending throughout the years, and video games takes about 30eur per month. That´s settled around bimonthly purchases, although I think it's more trimonthly with condensed couple purchases during Xmas period.

Time I can concentrate on gaming and Nintendo's release dates do help with this.

Whenever I feel like buying a game really. Sometimes I buy a game every few months, other times during a week to a few days but it's usually every few months since I tend to wait for price reductions.

Depending of the lineup. Last year I barely bought four games, but this year I intend to fill my 3DS list (Etrian Odyssey II Untold, Stella Glow, FE Fates, Nintendo Selects DKCR 3DS, Dragon Quest VIII, Pokemon Sun/Moon...)
Digital games depend of the discount.

Well.....

- For myself: 1 game every 2-3 months

Reason is that I have sooooo much other things to do. I don't have enough to play and purchase more. And of course theres other games that I still need to complete.

Generally once every few months.
But there are also times where I buy 3 games in one month.

As often as a game comes out that I want. I also have all gen 8 consoles and a gaming laptop. Used to be a lack of cash now it's a lack of time

That highly depends. There are years where I bought 0 games and there are years where I bought a dozen or more. If there's nothing of interest coming out, I'll buy nothing.

Depends if you mean old/vintage or new/relevant. Currently not many new games Gravity Rush and FFt0 are the last ones, last month.