Best practice for a lot of events pages for local business?

[WellCrafted]

I have a client that as part of their business they host "house concerts" several times a month.

Each event has its own page and then they have an overall calendar page that links to each of these event pages (it's a Wix website).

These event pages are promoted on outside pages and promoted by the artists themselves, so they attract quite a bit of outside traffic leading up to the event.

I'm stuck on what they should do with these event pages after the event is over because they add 30-50 event pages a year.

Do I let them live on the site for a length of time (like 6 months/year) and then delete the page and 301 redirect to the Calendar page?

Or it is better to just let them be and just exist on the website forever?

Which is better: a whole bunch of 301 redirects or a whole bunch of zero-traffic event pages?

Or is there an option I'm not considering? Using non-index?

 

[JS Girard]

... What SEO problem do these pages cause now? Or what actual problems do you worry they might cause in the future? Because if (say), they're not in Google's index now, then they're not doing anything either way and at first blush there does not seem to be any reason to worry.

 

[WellCrafted]

They are a new business, so they don't have a problem yet but I'm just thinking long term. That in the long run they'll have a whole bunch of useless pages that way outnumbers the 10 useful ones that actually have traffic. I'm concerned that could harm their SEO in the long run.

So google is indexing them now but probably will stop indexing them as they become irrelevant.

So are you thinking it's a non-issue?