How do growing startups manage their cashflow? - [i will not promote]

i will not promote I'm working with several early-stage companies and noticed a concerning pattern: brilliant product ideas but chaotic financial management, especially around accounts receivable. I'm curious about: 1. For those who've worked at/founded startups, what systems did you use to track who owes you money and when it's actually coming in? 2. How much time do you spend chasing payments each week? 3. What's your biggest frustration with getting paid on time? 4. Have you found any tools or methods that actually helped predict when clients will pay vs. when they say they'll pay? 5. For B2B startups: how do you balance maintaining good client relationships with ensuring timely payments? I'm putting together some research on this topic and would love to hear real experiences - both horror stories and success strategies welcome!