For most of us, leaking does happen within the first few weeks until we find the right appliance & products which work for our individual needs. It is a bit of "trial & error", but it only lasts for a short time until the right system is found. There is no, "one size fits all".
Everyone here is tops when it comes to advice on any issue you may have.
You can also contact the ostomy supply companies in advance of surgery and get familiar with their appliances and other ostomy products. They all have toll-free phone numbers.
I contacted Coloplast, Convatec, Hollister, Marlen, Cymed & Dansac for samples. All were fairly generous with pouch samples & products. I explained that I had never even seen an ostomy pouch before and wanted to know what to expect and familiarize myself with the process. They want your business, so they are happy to send samples.
In addition to numerous wafers and pouches, I was also able to get samples of Eakin and Adapt seals, just for asking. Hollister and Convatec also sent me their emergency kits which are very handy--canvas bags with scissors & mirrors. They will also send samples of stoma powder, paste, etc. All for free
I still call for samples if there is a new product I want to try.
This current thread has some good info about products and how to apply appliances.
https://www.healingwell.com/community/default.aspx?f=33&m=2480096