A mortgage agreement in principle takes into account your affordability for a property based on your deposit saved, household income and the price of the property. By having this in place, you have a good indication of whether the property you are viewing is achievable to purchase
It is a good idea to have a solicitor in mind and ready to instruct when needed. You will need a solicitor from the point that your offer has been accepted on a property.
If your purchase is dependent on the sale of a property, it is advisable to have that property on the market, if not under offer, before viewing properties to purchase.