I once had a friend who worked for the Bank of Canada in a highly secure building. The only way into the building and to the bike parking was using a secure key card. His never locked his bike because of the security. His bike was stolen and it had to be someone who worked in the building. This may be an anomaly but none the less happened. Panniers can wait, use a back pack you already have. Cycle in the day, so you don't need the light. Buy the best lock you can afford and when finances permit, then buy what you need.

I am one who is extremely careful with locking my bike. I have a bike compound that can only be opened with a key card and it also has video surveillance. I still use two Kyrptonite U locks with a Kryptonite cable and I leave these at work so I don't have to to carry them. In my business, I say anything that can be sold for a "piece of rock" is worthy of stealing for someone in need. Sad but true.