A pre-approval is a preliminary evaluation done by a lender, such as a bank or a mortgage broker, to determine the amount you can expect to borrow as maximum principal for the purchase of a home. Usually, the lender will also provide other terms, such as interest rate and the type of loan.
Typically, a mortgage payment amount may generally be no more than 28% of a borrower's monthly net income, but might depend on your lender. When taking out a mortgage, they may take into account your annual income, total monthly debt, a down payment, your debt-to-income ratio, or more, along with loan factors such as interest rate, the term, estimated taxes, and insurance when calculating how much they will lend.

The process can be lengthy depending on how long it takes to find a home. Once the offer is accepted on your chosen home, the average time is 30 to 45 days under normal market conditions. However, cash purchases can be completed much faster.

The market can affect the time it takes to complete a sale. If there are many sales, it may take longer as the parties involved - appraisers, inspectors, or lenders in the transaction, for example - get behind when business picks up. Lender turnaround times for loan underwriting may also slow down the process.
A seller's market is where the demand for homes increases, driving the prices up. This usually results from high demand for properties while there is a shortage.  

A buyer’s market typically has declining home prices and reduced demand, so it can take longer to close on a sale, giving buyers more time to consider buying a home.

Several factors may affect long-term and short-term demand.

The down payment varies in different real estate markets.

Conventional loans typically require a 20% down payment. However, there are many programs available that have a variety of down payment options. If the borrower pays Private Mortgage Insurance, or PMI, some loan programs are even available with as little as 3% down.

Consultation with a mortgage company or a bank regarding availability of specific programs with varying amounts of down payments is highly recommended.

The number of homes that you should view is not defined. Some home buyers view one home and decide it is the home for them. Others can take much longer and view several homes before deciding which one to purchase.

Overall, that’s up to you! Today, there are plenty of homes to view in a short time and the process has never been easier. However, nothing beats visiting a home to see how it looks and feels in person.

The amount of time the seller has is usually stated in the offer form. Typically, the seller contract will state the amount of time they have to respond to your offer. Typically, the seller has 24 hours to respond, but the time may vary depending on what is stated in the offer to purchase.

Final walkthroughs give buyers a chance to make sure that everything in the home is as you expected it. This is when the buyer ensures that the home is as agreed upon in the contract and makes certain that the buyer is satisfied with the home.