Trouser Shopping

I am being forced to go clothes shopping this weekend for black trousers. I really don't like clothes shopping. I tend to have items that I wear to death and that is the reason why I have to go shopping. I noticed yesterday that my faithful black trousers have gone threadbare just by the seat. I can't risk wearing them to work anymore as I don't want to subject the public to the horror of a view of my bottom. I'm not at all adventurous with clothes and tend to play it safe , hence the compulsory black trousers. My last pair was from Marks and Spencer's so that is where I will start, if I am lucky I could be in and out within 20 minutes.
In addition to the trouser situation, the heel also went on my faithful black boots. I've  had my boots for about 2 years and wear them all the time. I get them resoled and heeled when I need but looking at the heel it has split vertically and I'm not sure they are repairable. I will have to take them into the cobblers shop and see what he says. Luckily I have a pair in reserve. The boots were so comfortable that when I saw another pair on sale I bought them to keep for a later date.