What to check after changing website theme

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  Melissa Baroni: I`d run and save a Screaming Frog crawl before the change to be safe. That way you can check that your alt tags and any other meta data made it through unscathed. Good luck! 😀
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  Michael Stricker: Gbot access to all resources without blocking. Configuration of page creation, numbered pages, dated pages, tag pages, pagination.
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  Tony McCreath: I often see content being removed, because it does not fit the theme. Especially on the home page.
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  Yuliana Kronrod: I’ve had a reskin result in GTM loss
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  Michael Stricker: Yuliana Kronrod right! Test those pixels and conversion trackers.
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  Dave Elliott: I`d be checking conversion rates carefully in say 30 days time
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  Micah Fisher-Kirshner: Dave that seems like a long time to check...?
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  Dave Elliott: Depends on how much traffic you get. But even high traffic sites id want was a couple of weeks data to make a decision....unless it drops of a genuine cliff.
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  Micah Fisher-Kirshner: I feel like 2 weeks max (obviously depending on one`s conversion timeline) is the way to go as that`s a long wait for potentially lower conversation numbers
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  Benj Arriola: If it’s a look and feel change and URLs and functionality is still the same then what I would check is possible JavaScript errors, like content not appearing when JavaScript is disabled. I would particularly look at sliders, accordion navigations, tabbed areas, collapsing and expanding divs, scrollbars within a page, infinite scroll effects, floating items, lightbox modals, etc. Even if iframes, and flash are outdated, I’ll still check for the presence of its use.
  
  Not that JavaScript can’t be used, it can but should be used correctly.
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  Michael Stricker: Any add-ons or plug-ins would be suspect after such reskin. Schema. Pagination. Breadcrumbs. Auto-generated Links to relevant or popular content. As Benj said, sliders, pop-ups and persistent share tools. But scroll-triggered features and such.
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  Doc Sheldon: Others have already mentioned the obvious stuff, but a few that have bitten me are lost canonicals, screwed up pagination, broken deferred loading and messed-up CSS. Were they running a child theme before the change? If so, you can probably capture a lot of the customization from a copy of that, so you won`t have to rewrite it all.
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  Michael Martinez: Look for "nofollow" attributes on internal links and hidden or unauthorized outbound links.