The more people that put out feeders the better, because as birdwoman rightly says some species are almost dependant on kind folk like yourself for their food as some habitats are fast disappearing. You might want to add a seed feeder in another part of your garden to encourage still more birds,not forgetting fresh water daily summer and winter. Water is vital, not only to drink but to keep feathers in perfect flying order.
July and the beginning of August is generally known as the quiet period in the birdy world as parents are busy making sure the youngsters can look after themselves before leaving home and there is also an abundant supply of bugs and other natural food, so they may not come to feeders quite so often.
Will the nesting birds breed more than they lose? Yes, especially Blue Tits and their cousins, Great and Coal. They have between 7- 16 eggs, so they still thrive allowing for heat, cats, rats the occasional woodpecker and any other predator. It's great fun watching them - have fun:-)