How do you estimate market size for a new SaaS product?

For a quick B2B SaaS TAM, I usually start with industry reports from Gartner or IDC, then cross-check with LinkedIn Sales Navigator to count actual companies/roles that fit your ICP — that gets you to a real SAM fast. For SOM, just be honest: what can your sales motion realistically reach in 12-24 months given your team size? A lot of people overthink the top-down TAM and underwork the bottom-up SOM, which is the number investors actually care about.