Need to replumb under sink for new disposal

I am replacing the disposal under my kitchen sink. The new disposal is a littl bigger than the old one and the pipes need to move a little.

The existing drain pipes are 1 1/2" PVC. All glued together.

When I was at the plumbing supply store buying new PVC fittings, a plumber suggested I replace all the 1 1/2" PVC with the smaller, thinner, slip joint fittings to make it easier next time.

I like the idea of easier next time, but it seems it would be better for the sink and the disposal if I kept the drain diameter 1 1/2".

Can I get some opinions on which way to go?

Thanks!
Ron

The thinner tubular drain pieces are not significantly smaller than PVC in the inside diameter. Unless you have some special need
for the added sturdiness of Schedule 40 PVC, the 1 1/2 in. tubular is the way to go, the flimsier stuff is perfectly adequate
for the job it needs to do, and much more convenient.