Should I include changefreq and priority columns?

If they're in the source sitemap, yes — they're free metadata to keep. If you're generating a CSV for downstream tools, both are usually safe to drop. Google has publicly confirmed it ignores both <changefreq> and <priority> when crawling. Bing reportedly still uses changefreq as a weak signal. For analytics workflows, changefreq is rarely actionable; priority is even less so since most CMS generators set it to 1.0 on everything. Where they help: spotting CMSes that diligently set per-URL values (a sign of a careful SEO setup) and pre-filtering — e.g. 'crawl only URLs with priority ≥ 0.8'. xmlsitemapmaker.com only writes these columns when the source sitemap has them, so empty data doesn't bloat the CSV.