Google has released out some recent updates which allow for and some cases override meta descriptions to a maximum of 375 characters, instead of the standard 155 characters limit.
Should you use the new meta description length?
Well yes... and no.
This new 300 character limit allows for obviously more real estate space on google. Also, an opportunity for further explanation for selling services, listing additional services or highlighting longer snippets from blogs. The problem occurs when other search consoles read your site, it won't be the same limit so it may lead to some odd looking cut offs if you've not prepared or thought about it. Additionally to this, should Google ever revert to the older settings then you're stuck reverting back all your content.
My advice? Ensure your SEO plugins (if on WordPress) is up to date with the latest versions. Then include or writeup the 375 character improvements on your vital pages and keep track of the pages you've adjusted the limits for. This way should google revert back or you see increase/decrease in conversions/site traffic you can act accordingly over time.
Research from Moz suggests that the ideal new length should be around 300 characters
For more SEO information for 2018 and beyond, check out our guide to SEO in 2018 and beyond