Open the site on your phone using mobile data, not Wi-Fi. Time how many seconds it takes for the first screen with text to appear.
Benchmark: under 2 seconds. 3 seconds is tolerable but already bad. 5 seconds or more and people leave before it loads.
Quick check: Google PageSpeed Insights. Enter your site address. If the mobile score is below 50, that is a problem.
What to look for: the red zone in the report usually means heavy images, slow hosting, or too many scripts.
Но важно: без проработки структуры кампаний и семантики бюджет просто сливается.