Some companies can react within 24 hours to a customer asking the price of a product, while other companies (often EU located firms) take months to respond. Possibly the longest time ever are for scientific instrument manufacturers - some NEVER reply to a single inquiry, it takes multiple tries to get their attention.
All of which results in loss of customer interest. If a company takes 6 months to reply to a purchase inquiry, imagine how long it takes for them to honor a guarantee of the product? Got a problem with their product, good luck with that.
The best companies, no matter how large they are, no matter if their sales are billions of dollars every year, will answer an inquiry within 72 hours. They stay hungry for customers, as they should
European companies are often the worst in trying to get their attention. They act as if they have no sales department when they wait a month, 3 months, 6 months, to reply to an email asking for a quote on a product. They may as well go out of business completely after such a long delay.
American outposts of European companies are usually a little faster than communicating directly with the European manufacturer. They have to earn their pay the hard way, with sales. But in Europe, one wonders how those comatose companies stay in business. Maybe they don't need the money anymore?
Want to be above average in sales? Get a reply out immediately. Don't wait for approval from the home office, just get in contact now before the customer finds another source for the same product.
Business people have to keep their businesses moving along, so when they don't get a prompt reply to a request for a quote, they have to decide whether it is worth waiting or whether to just get the job done with whatever else is available.
Russian firms need to keep in mind that in the West, businesses make decisions and move quickly, so getting them the information they need is time-critical. Speed is everything. Tomorrow may be too late for making the sale.