Build a Robust Scraper with Fallbacks

Make my web scraper more reliable and handle common problems.

Language: [Python, JavaScript, etc.]
Current code: [paste your scraper or describe it]

Problems I want to handle:
1. Websites that block my requests (403 errors)
2. Elements that sometimes don't exist on a page
3. Rate limiting (too many requests too fast)
4. Network timeouts and connection errors
5. Data that needs cleaning (extra whitespace, weird characters)

Requirements:
1. Add retry logic for failed requests (try 3 times before giving up)
2. Use realistic browser headers so I don't look like a bot
3. Add random delays between requests (1-3 seconds)
4. Gracefully skip items with missing data instead of crashing
5. Log what worked and what failed for debugging

Optional: Add proxy support for when my IP gets blocked.

I'm learning, so explain why sites block scrapers and how these techniques help.